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Sample Business Contracts

California-Redwood City-450 Broadway Build to Suit Lease - Martin/Campus Associates LP and At Home Corp.

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                               BUILD TO SUIT LEASE
 
                                 BY AND BETWEEN
 
                         MARTIN/CAMPUS ASSOCIATES, L.P.
 
                                   "LANDLORD"
 
                                       AND
 
                               AT HOME CORPORATION
 
                                    "TENANT"
 
          FOR THE APPROXIMATELY 86,418 SQ. FT. PREMISES AT 450 BROADWAY
                             REDWOOD CITY, CA 94063 
 
                                  LEASE SUMMARY
                                  -------------

  Lease Date:              _____________________________________

 Landlord:                Martin/Campus Associates, L.P.

 Address of Landlord:     100 Bush Street, 26th Floor
                          San Francisco, CA 94104

 Tenant:                  At Home Corporation

 Address of Tenant:       425 Broadway
                          Redwood City, CA

 Contact:                 Kenneth Goldman

 Telephone:               (650) 569-5353

 Building Address:        450 Broadway
                          Redwood City, California

 Total Building Square Footage:     Approximately 86,418 square feet

 Term:                              approximately fifteen years
                                    (see Paragraph 4.A.)

 Monthly Rent:            As provided under Paragraph 5.A, and subject to
                                            -------------
                          adjustment pursuant to Paragraph 4.C and 5.B
                                                 -------------     ---

 Security Deposit:        An amount equal to three (3) payments of the initial
                          Monthly Rent (see Paragraph 7)
                                            ----------- 

 Exhibit A:     Premises
 Exhibit B:     Work Letter Agreement 
 Exhibit C:     Site Plan for Project 
 Exhibit D:     Commencement Date Memorandum
 Exhibit E:     Subordination, Nondisturbance and Attornment Agreement
 Exhibit F:     Option to Purchase Terms

 
                                TABLE OF CONTENTS
                                -----------------

 1.   Parties............................................... 2

 2.   Premises.............................................. 2

 3.   Definitions........................................... 2
 
      A.     Affiliate...................................... 2
      B.     Alterations.................................... 2
      C.     Broadway Lease................................. 2
      D.     Capital Improvements........................... 3
      E.     CC&Rs.......................................... 3
      F.     Collateral Agreements.......................... 3
      G.     Commencement Date.............................. 3
      H.     Common Area.................................... 3
      I.     Common Area Maintenance Costs.................. 3
      J.     Final Plans.................................... 5
      K.     HVAC........................................... 5
      L.     Impositions.................................... 6
      M.     Improvements................................... 6
      N.     Index.......................................... 6
      O.     Interest Rate.................................. 6
      P.     INTENTIONALLY DELETED.......................... 6
      Q.     Landlord's Agents.............................. 6
      R.     Lease Year..................................... 7
      S.     Monthly Rent................................... 7
      T.     Parking Area................................... 7
      U.     Person......................................... 7
      V.     Project........................................ 7
      W.     Real Property Taxes............................ 7
      X.     Rent........................................... 8
      Y.     Rentable Area.................................. 8
      AA.    Security Deposit............................... 8
      BB.    Sublet......................................... 8
      CC.    Subrent........................................ 9
      DD.    Subtenant...................................... 9
      EE.    Tenant Delay................................... 9
      FF.    Tenant Improvements............................ 9
      GG.    Tenant's Percentage Share...................... 9
      HH.    Tenant's Personal Property..................... 9
      II.    Term...........................................10
      JJ.    Fixed Charge Ratio.............................10

 4. Lease Term..............................................10
      A.     Term...........................................10 

 

                                                          
      B.    Delays in Completion........................... 10
      C.    Option to Extend............................... 10

 5.   Rent and Additional Charges.......................... 13
 
      A.    Monthly Rent................................... 13
      B.    Adjustments to Monthly Rent.................... 14
      C.    Management Fee................................. 14
      D.    Common Area Maintenance Costs.................. 15
      E.    Additional Rent................................ 16
      F.    Prorations..................................... 16
      G.    Interest....................................... 16

 6.   Late Payment Charges................................. 16

 7.   Security Deposit..................................... 17
 
      A.    Deposit Required............................... 17

 8.   Holding Over......................................... 18

 9.   Tenant Improvements.................................. 19

 10.  Condition of Premises................................ 19
      A.    Capital Improvements........................... 19
      B.    Acceptance of Premises......................... 19

 11.  Use of the Premises and Common Area.................. 19
      A.    Tenant's Use................................... 20
      B.    Hazardous Materials............................ 20
      C.    Special Provisions Relating to The Americans
            With Disabilities Act of 1990.................. 24
      D.    Use and Maintenance of Common Area............. 25

 12.  Quiet Enjoyment...................................... 25

 13.  Alterations.......................................... 26
      A.    Alteration Rights.............................. 26
      B.    Performance of Alterations..................... 26
      C.    Trade Fixtures................................. 26

 14.  Surrender of the Premises............................ 27

 15.  Impositions and Real Property Taxes.................. 27
      A.    Payment by Tenant.............................. 27
      B.    Taxes on Tenant Improvements and Personal
            Property....................................... 28
      C.    Proration...................................... 29

 16.  Utilities and Services............................... 29 

 

 17.  Repair and Maintenance..............................  29
      A.    Landlord's Obligations........................  29
      B.    Tenant's Obligations..........................  30
      C.    Conditions Applicable to Repairs..............  31
      D.    Landlord's Rights.............................  31
      E.    Compliance with Governmental Regulations......  31

 18.  Liens...............................................  31

 19.  Landlord's Right to Enter the Premises..............  32

 20.  Signs...............................................  32

 21.  Insurance...........................................  32
      A.    Indemnification...............................  32
      B.    Tenant's Insurance............................  33
      C.    Premises Insurance............................  34
      D.    Increased Coverage............................  34
      E.    Failure to Maintain...........................  34
      F.    Insurance Requirements........................  35
      G.    Waiver and Release............................  35

 22.  Waiver of Subrogation...............................  35

 23.  Damage or Destruction...............................  36
      A.    Landlord's Obligation to Rebuild..............  36
      B.    Right to Terminate............................  36
      C.    Limited Obligation to Repair..................  37
      D.    Abatement of Rent.............................  37
      E.    Damage Near End of Term.......................  37

 24.  Condemnation........................................  37

 25.  Assignment and Subletting...........................  38
      A.    Landlord's Consent............................  38
      B.    Tenant's Notice...............................  38
      C.    Information to be Furnished...................  38
      D.    Landlord's Alternatives.......................  39
      E.    Proration.....................................  39
      F.    Parameters of Landlord's Consent..............  39
      G.    Permitted Transfers...........................  40

 26.        Default.......................................  40
      A.    Tenant's Default..............................  40
      B.    Remedies......................................  41  

                                                          
      C.    Landlord's Default............................  42

 27.  Subordination.......................................  42
      A.    Subordination.................................  42
      B.    Attornment....................................  43
      C.    Non-Disturbance...............................  43

 28.  Notices.............................................  43

 29.  Attorneys' Fees.....................................  44

 30.  Estoppel Certificates...............................  44

 31.  Transfer of the Premises by Landlord................  45

 32.  Landlord's Right to Perform Tenant's Covenants......  45

 33.  Tenant's Remedy.....................................  45

 34.  Mortgagee Protection................................  45

 35.  Brokers.............................................  46

 36.  Acceptance..........................................  46

 37.  Parking.............................................  46

 38.  Right of First Offer to Purchase....................  46
      A.    Notice of Sale................................  47
      B.    Acceptance....................................  47
      C.    Rejection.....................................  47
      D.    Offered Terms.................................  48
      E.    Acceptance of Tenant's Offer..................  48
      F.    Conditions....................................  48
      G.    Process.......................................  48
      H.    Rights Personal...............................  49

 39.  General.............................................  49
      A.    Captions......................................  49
      B.    Executed Copy.................................  49
      C.    Time..........................................  49
      D.    Separability..................................  49
      E.    Choice of Law.................................  49
      F.    Gender; Singular, Plural......................  49
      G.    Binding Effect................................  49
      H.    Waiver........................................  50  

                                                            
      I.    Entire Agreement..............................  50
      J.    Authority.....................................  50
      K.    Exhibits......................................  50
      L.    Lease Summary.................................  50
      M.    Memorandum of Lease...........................  50   
 
                                  BUILD TO SUIT LEASE
                                  -------------------
 
      1.   Parties.
           ------- 
 
           THIS BUILD TO SUIT LEASE (the "Lease"), dated as of ________ 1997, is
entered into by and between MARTIN/CAMPUS ASSOCIATES, L.P., a Delaware limited partnership
("Landlord"), whose address is 100 Bush Street, San Francisco, CA
               --------                                                        94104,
and AT HOME CORPORATION, a Delaware corporation ("Tenant"), whose address
                                                          ------               
  is 425 Broadway, Redwood City, CA.
 
      2.   Premises.
           -------- 
 
           Landlord hereby leases to Tenant and Tenant hereby leases from Landlord
those certain premises to situated in a building to be constructed by Landlord pursuant
to the terms of this Lease which shall be commonly known as 450 Broadway (the "Building"),
in the City of Redwood City, County of San Mateo,
                    --------                                                   
  State of California, as more particularly shown on Exhibit A (the "Premises"),
                                                    ---------       --------   
which Premises shall consist of a total area of approximately 86,418 square feet.
 On or before the Commencement Date, Landlord shall measure the Rentable Area of
the Premises in accordance with BOMA Standard (ANSI Z65.1 1980) for full floor office
occupancy, and Landlord and Tenant shall amend this Lease if necessary to reflect
any discrepancy in the size of the Premises disclosed by Landlord's measurement
of the Premises by Landlord's architect.  The Premises also includes the appurtenant
right to use in common with other tenants of the Project (as defined below) the
Common Area (as defined below) of the Project owned by Landlord.
 
      3.   Definitions.
           ----------- 
 
           The following terms shall have the following meanings in this Lease:
 
           A.  Affiliate.  Any Person that controls, or is controlled by or is
               ---------                                                       under
common control with, Landlord or Tenant.  No Person shall be deemed in control of
another simply by virtue of being a partner, director, officer or holder of voting
securities of any Person.  For purposes of this Paragraph 3.A,
                                                                  -------------
 "control" shall mean the ownership of, and/or the right to vote, stock, partnership
interests, membership interests, or other indicia of ownership possessing at least
fifty-one percent (51%) of either the total combined interests in a Person, or the
voting power of all classes of a Person's capital stock, partnership interests,
membership interests, or other indicia of ownership, that have been issued, outstanding,
and (if applicable) are entitled to vote.
 
           B.   Alterations.  Any alterations, additions or improvements made in,
                -----------                                                    
  on or about the Premises after the substantial completion of the Improvements,
including, but not limited to, lighting, heating, ventilating, air conditioning,
electrical, partitioning, drapery and carpentry installations.
 
           C.  Broadway Lease.  That certain lease dated as of October 18, 1996,
               --------------                                                  
 by and 
 
                                        2 

 between Landlord and Tenant, for those certain premises commonly known as 425 Broadway,
situated in the City of Redwood City, County of San Mateo, State of California.
 
           D.  Capital Improvements.  Those certain improvements to the Building
               --------------------                                            
 to be constructed by Landlord pursuant to Paragraph 10.A and the Work Letter
                                           --------------                     Agreement
attached to this Lease as Exhibit B (the "Work Letter").
                                     ---------       -----------   
 
           E.  CC&Rs.  Any declaration of conditions, covenants and/or
               -----                                                   restrictions,
or similar instrument, that now encumbers, or may in the future encumber the Project
or the Premises, as adopted by Landlord or its successors in interest from time
to time, and any modifications or amendments thereto.
 
           F.  Collateral Agreements.  The following agreements: (i) the Broadway
               ---------------------                                           
  Lease, (ii) that certain Build to Suit Option Agreement by and between Landlord
and Tenant, dated as of October 25, 1996 (the "Build to Suit Agreement"), (iii)
                                                -----------------------        
 that certain Agreement Granting Rights of First Offer, by and between Landlord
and Tenant, dated as of October 25, 1996, (iv) that certain Warrant to Purchase
Series A Common Stock of At Home Corporation and that certain Second Amended and
Restated Registration Rights Agreement, executed by Landlord, Tenant and certain
other parties, each dated as of October 18, 1996 (collectively, the "Warrant
                                                                      ------- Agreement"),
and (v) any leases at any time executed by Tenant arising out of - ---------   
                                                                 Tenant's exercise
of any of its rights set forth in the agreements described in items (ii) and (iii)
above.
 
           G.  Commencement Date.  The Commencement Date of this Lease shall be
               -----------------       the first day of the Term determined in accordance
with Paragraph 4.A.
                                                         ------------- 
 
           H.  Common Area. All areas and facilities within the Project not
               -----------                                                  appropriated
to the exclusive occupancy of tenants, including the Parking Area, the sidewalks,
pedestrian ways, driveways, signs, pools, ponds, service delivery facilities, common
storage areas, common utility facilities and all other areas in the Project established
by Landlord and/or its successors for non-exclusive use. Landlord may, by written
notice to Tenant, elect in its sole discretion to increase and/or decrease the Common
Area from time to time during the Term for any reason whatsoever (including without
limitation an election by Landlord and/or its successors in their sole discretion
to make changes to the buildings situated in the Project, and/or to subdivide, sell,
exchange, dispose of, transfer, or change the configuration of all or any portion
of the Common Area from time to time), so long as Landlord neither unreasonably
interferes with ingress to or egress from the Building, nor permanently reduces
the number of parking spaces available for Tenant's use below the minimum requirements
set forth in Paragraph 37.  No such subdivision, sale, exchange, disposition, transfer,
or change to the configuration of all or any portion of the Common Area shall cause
the Common Area to be increased or decreased unless and until Landlord has given
Tenant written notice of such increase or decrease.
 
           I.  Common Area Maintenance Costs.  The total of all costs and
               -----------------------------                              expenses
paid or incurred by Landlord in connection with the operation, maintenance, ownership
and repair of the Common Area, and the performance of Landlord's obligations under
Paragraphs 17.A and 17.E.  Without limiting the
                              ---------------     ----                        generality
of the foregoing, Common Area Maintenance 
 
                                        3 

 Costs include all costs of and expense for: (i) maintenance and repairs of the
Common Area; (ii) resurfacing, resealing, remarking, painting, repainting, striping
or restriping the Parking Area; (iii) maintenance and repair of all public or common
facilities; (iv) maintenance, repair and replacement of sidewalks, curbs, paving,
walkways, Parking Area, Project signs, landscaping, planting and irrigation systems,
trash facilities, loading and delivery areas, lighting, drainage and common utility
facilities, directional or other signs, markers and bumpers, and any fixtures, equipment
and personal property located on the Common Area; (v) wages, salaries, benefits,
payroll burden fees and charges of personnel employed by Landlord and the charges
of all independent contractors retained by Landlord (to the extent that such personnel
and contractors are utilized by Landlord) for the maintenance, repair, management
and/or supervision of the Project, and of any security personnel retained by Landlord
in connection with the operation and maintenance of the Common Area (although Landlord
shall not be required to obtain security services); (vi) maintenance, repair and
replacement of security systems and alarms installed by Landlord (if any); (vii)
depreciation or amortization (or in lieu thereof, rental payments) on all tools,
equipment and machinery used in the operation and maintenance of the Common Area;
(viii) premiums for Comprehensive General Liability Insurance or Commercial General
Liability Insurance, casualty insurance, workers compensation insurance or other
insurance on the Common Area, or any portion thereof or interest therein, and any
deductibles payable with respect to such insurance policies; (ix) all personal property
or real property taxes and assessments levied or assessed on the Project, or any
portion thereof or interest therein, including without limitation the Real Property
Taxes for the Project, if applicable under Paragraph 15.A; (x) cleaning, collection,
                                  -------------- storage and removal of trash, rubbish,
dirt and debris, and sweeping and cleaning the Common Area; (xi) legal, accounting
and other professional services for the Project, including costs, fees and expenses
of contesting the validity or applicability of any law, ordinance, rule, regulation
or order relating to the Building, and of contesting, appealing or otherwise attempting
to reduce any Real Property Taxes assessed against the Project; (xii) any alterations,
additions or improvements required to be made to the Common Area in order to reduce
Common Area Maintenance Costs or to protect the health or safety of occupants of
the Project, provided that the cost of any such alterations, additions, improvements
or capital improvements, together with interest at the Interest Rate, shall be amortized
over the useful life of the alteration, addition, improvement or capital improvement
in question and included in Common Area Maintenance Costs for each year over which
such costs are amortized; (xiii) all costs and expenses of providing, creating,
maintaining, repairing, managing, operating, and supervising an amenity center for
the Project, which may include without limitation a dining facility (provided, however,
that Landlord shall not be required to provide or create such an amenity center),
which costs and expenses may include without limitation rent charged by Landlord
for the space occupied by such amenity center; (xiv) all costs and expenses incurred
by Landlord in performing its obligations under Paragraphs 17.A or 17.E, including
                                              ----------------------- without limitation
all costs and expenses incurred in performing any alterations, additions or improvements
required to be made to the Building in order to comply with applicable laws, ordinances,
rules, regulations and orders and all capital improvements required to made in connection
with the operation, maintenance and repair of the Building, provided that the cost
of any such alterations, additions, improvements or capital improvements, together
with interest at the Interest Rate, shall be amortized over the useful life of the
alteration, addition, improvement or capital improvement in question and included
in Common Area Maintenance Costs for each
 
                                        4 

 year over which such costs are amortized; (xv) all costs and expenses incurred
in performing any alterations, additions or improvements required to be made to
the Common Area in order to comply with applicable laws, ordinances, rules, regulations
and orders and all capital improvements required to made in connection with the
operation, maintenance and repair of the Common Area, provided that the cost of
any such alterations, additions, improvements or capital improvements, together
with interest at the Interest Rate, shall be amortized over the useful life of the
alteration, addition, improvement or capital improvement in question and included
in Common Area Maintenance Costs for each year over which such costs are amortized;
(xvi) any and all payments due and owing on behalf of the Project or any portion
thereof with respect to any CC&Rs, including without limitation any and all assessments
and association dues; (xvii) any other cost or expense which this Lease expressly
characterizes as a Common Area Maintenance Cost, and (xviii) all costs and expenses
related to the adoption and maintenance of a portion of Highway 101. However, notwithstanding
the foregoing or anything to the contrary in this Lease, Common Area Maintenance
Costs shall not include the cost of or expenses for the following: (A) leasing commissions,
attorneys' fees or other costs or expenses incurred in connection with negotiations
or disputes with other tenants of the Project; (B) depreciation of buildings in
the Project; (C) payments of principal, interest, late fees, prepayment fees or
other charges on any debt secured by a mortgage covering the Project, or rental
payments under any ground lease or underlying lease; (D) any penalties incurred
due to Landlord's violation of any governmental rule or authority (but not excluding
the cost of compliance therewith, if such cost is chargeable to Tenant pursuant
to this Lease); (E) any Real Property Taxes or costs for which Landlord is separately
and directly reimbursed by Tenant or any other tenant of the Project which are assessed
against the Premises or the premises leased by such other tenant(s); (F) items for
which Landlord is reimbursed by insurance; (G) all costs arising from monitoring,
cleaning up and otherwise remediating any release of Hazardous Materials at the
Premises that has been specifically identified by Landlord and Tenant in writing
as of the date of the Lease; (H) all costs associated with the operation of the
business of the entity which constitutes "Landlord", as distinguished from the costs
of operations, including, but not limited to, costs of partnership accounting and
legal matters, costs of defending any lawsuits with any mortgagee (except as the
actions of Tenant may be in issue), costs of selling, syndicating, financing, mortgaging,
or hypothecating any of the Landlord's interest in the Project and/or Common Area,
or any portion thereof, costs of any disputes between Landlord and its employees,
costs of disputes of Landlord with Building management or costs paid in connection
with disputes with Tenant or any other tenants; (I) all costs (including permit,
license and inspection fees) incurred in renovating or otherwise improving or decorating,
painting or redecorating space for other tenants in the Project; (J) the creation
of any reserves for equipment or capital replacement (but not the expenditure of
any funds from such reserves); and (K) all costs arising from monitoring, cleaning
up and otherwise remediating any release of Hazardous Materials at the Premises
to the extent that Landlord (who shall use reasonable efforts to obtain reimbursement)
is actually reimbursed by third parties for such costs (but not the costs of collection
incurred by Landlord, unless such costs of collection are also reimbursed by third
parties).
 
           J.  Final Plans.  As defined in the Work Letter.
               -----------                    
 
           K.  HVAC.  Heating, ventilating and air conditioning.
               ---- 
 
                                        5 
 
           L.  Impositions.  Taxes, assessments, charges, excises and levies,
               -----------                                                    business
taxes, license, permit, inspection and other authorization fees, transit development
fees, assessments or charges for housing funds, service payments in lieu of taxes
and any other fees or charges of any kind at any time levied, assessed, charged
or imposed by any federal, state or local entity, (i) upon, measured by or reasonably
attributable to the cost or value of Tenant's equipment, furniture, fixtures or
other personal property located in the Premises, or the cost or value of any Alterations;
(ii) upon, or measured by, any Rent payable hereunder, including any gross receipts
tax; (iii) upon, with respect to or by reason of the development, possession, leasing,
operation, management, maintenance, alteration, repair, use or occupancy by Tenant
of the Premises, or any portion thereof; or (iv) upon this Lease transaction, or
any document to which Tenant is a party creating or transferring any interest or
estate in the Premises. Impositions do not include franchise, transfer, inheritance
or capital stock taxes, or income taxes measured by the net income of Landlord from
all sources, except to the extent any such taxes are levied or assessed against
Landlord as a substitute for, in whole or in part, any item that would otherwise
be deemed an Imposition under this paragraph.
 
           M.  Improvements.  Collectively, the Tenant Improvements and the
               ------------                     Capital Improvements.
 
           N.  Index.  The Consumer Price Index, All Urban Consumers, All Items,
               -----                                                           
 published by the U.S. Department of Labor, Bureau of Labor Statistics for the San
Francisco-Oakland-San Jose Metropolitan Area (1982-84=100).  If the Base Year of
the Index is changed, then all calculations pursuant to this Lease which require
the use of the Index shall be made by using the appropriate conversion factor published
by the Bureau of Labor Statistics (or successor agency) to correlate to the Base
Year of the Index herein specified.  If no such conversion factor is published,
then Landlord shall, if possible, make the necessary calculation to achieve such
conversion. If such conversion is not in Landlord's good-faith, business judgment
possible, or if publication of the Index is discontinued, or if the basis of calculating
the Index is materially changed, then the term "Index" shall mean comparable statistics
on the cost of living, as
                -----                                                          
  computed either (i) by an agency of the United States Government performing a
function similar to the Bureau of Labor Statistics, or (ii) if no such agency performs
such function, by a substantial and responsible periodical or publication of recognized
authority most closely approximating the result which would have been achieved by
the Index, as may be determined by Landlord in the exercise of its reasonable good
faith business judgment.
 
           O.  Interest Rate.  Either (i) the greater of (a) twelve percent
               -------------                                                (121%)
per annum, or (b) the reference rate, or succeeding similar index, announced from
time to time by the Bank of America's main San Francisco office, plus three percent
(3%) per annum; or (ii) the maximum rate of interest permitted by law, whichever
is less.
 
           P.  INTENTIONALLY DELETED
 
           Q.  Landlord's Agents.  Landlord's authorized agents, partners,
               -----------------              subsidiaries, directors, officers,
and employees.
 
                                        6 
 
           R.  Lease Year.  A period of twelve (12) consecutive calendar months
               ----------                                                      
during the Term, commencing with the Commencement Date if the Commencement Date
is the first day of a calendar month, or commencing with the first day of the month
following the Commencement Date if the Commencement Date is not the first day of
a calendar month.  The first Lease Year shall include the period between the Commencement
Date and the first day of the month following the Commencement Date if the Commencement
Date is not the first day of a calendar month.  The last Lease Year shall consist
of the period between the date on which the Term expires or terminates and the day
after the last day of the preceding Lease Year.
 
           S.  Monthly Rent.  The rent payable pursuant to Paragraph 5.A., as
               ------------                                -------------- adjusted
from time to time pursuant to the terms of this Lease.
 
           T.  Parking Area.  All Common Area (except sidewalks and service
               ------------                                                 delivery
facilities) now or hereafter designated by Landlord for the parking or access of
motor vehicles, including roads, traffic lanes, vehicular parking spaces, landscaped
areas and walkways, and including any parking structure constructed during the Term.
 Landlord and/or its successors may, by written notice to Tenant, elect in their
sole discretion to increase and/or decrease the Parking Area from time to time during
the Term for any reason whatsoever (including without limitation an election by
Landlord and/or its successors in their sole discretion to make changes to the buildings
situated in the Project, and/or to subdivide, sell, exchange, dispose of, transfer,
or change the configuration of all or any portion of the Parking Area from time
to time), so long as such changes to the Parking Area do not permanently reduce
the number of parking spaces available for Tenant's use below the minimum requirements
set forth in Paragraph 37.  No such subdivision, sale, exchange, disposition,
          ------------                                                     transfer,
or change to the configuration of all or any portion of the Parking Area shall cause
the Parking Area to be increased or decreased unless and until Landlord has given
Tenant written notice of such increase or decrease.
 
           U.  Person.  Any individual, partnership, firm, association,
               ------                   corporation, limited liability company,
trust, or other form of business or legal entity.
 
           V.  Project.  That certain real property shown on Exhibit C.  Landlord
               -------                                       ---------         
  and/or its successors may, by written notice to Tenant, elect in their sole discretion
to increase and/or decrease the number of buildings and/or the amount of Rentable
Area situated in the Project from time to time during the Term for any reason whatsoever.
 
           W.  Real Property Taxes.  Taxes, assessments and charges now or
               -------------------                                         hereafter
levied or assessed upon, or with respect to, the Project, or any personal property
of Landlord used in the operation thereof or located therein, or Landlord's interest
in the Project or such personal property, by any federal, state or local entity,
including: (i) all real property taxes and general and special assessments; (ii)
charges, fees or assessments for transit, housing, day care, open space, art, police,
fire or other governmental services or benefits to the Project, including assessments,
taxes, fees, levies and charges imposed by governmental agencies for such purposes
as street, sidewalk, road, utility construction and maintenance, refuse removal
and for other governmental services; (iii) service payments in lieu of taxes; (iv)
any tax, fee or excise on the use or occupancy of any part of the Project, or on
rent for space in the Project; (v) any other tax, 
 
                                        7 

 fee or excise, however described, that may be levied or assessed as a substitute
for, or as an addition to, in whole or in part, any other Real Property Taxes; and
(vi) reasonable consultants, and attorneys' fees and expenses incurred in connection
with proceedings to contest, determine or reduce Real Property Taxes. Real Property
Taxes do not include: (A) franchise, transfer, inheritance or capital stock taxes,
or income taxes measured by the net income of Landlord from all sources, unless
any such taxes are levied or assessed against Landlord as a substitute for, in whole
or in part, any Real Property Tax; (B) Impositions and all similar amounts payable
by tenants of the Project under their leases; and (C) penalties, fines, interest
or charges due for late payment of Real Property Taxes by Landlord. If any Real
Property Taxes are payable, or may at the option of the taxpayer be paid, in installments,
such Real Property Taxes shall, together with any interest that would otherwise
be payable with such installment, be deemed to have been paid in installments, amortized
over the maximum time period allowed by applicable law. If the tax statement from
a taxing authority does not allocate Real Property Taxes to the Building, Landlord
shall make the determination of the proper allocation of such Real Property Taxes
based, to the extent possible, upon records of the taxing authority and, if not
so available, then on an equitable basis.
 
           X.  Rent.  Monthly Rent plus the Additional Rent as defined in
               ----                         Paragraph 5.E. - ------------- 
 
           Y.  Rentable Area.  The aggregate square footage in any one or more
               -------------                                                   buildings
in the Project, as appropriate, as reasonably determined by Landlord's architect
from time to time in accordance with BOMA Standard (ANSI Z65.1 1980) for full floor
office occupancy.
 
           AA. Security Deposit.  That amount paid by Tenant pursuant to
               ----------------               Paragraph 7. - ----------- 
 
           BB. Sublet.  Any transfer, sublet, assignment, license or concession
               ------                                                          
agreement, change of ownership, mortgage, or hypothecation of this Lease or the
Tenant's interest in the Lease or in and to all or a portion of the Premises. As
used herein, a Sublet includes the following: (i) if Tenant is a partnership or
a limited liability company, a transfer, voluntary or involuntary, of all or any
part of any interest in such partnership or limited liability company, or the dissolution
of the partnership or limited liability company, whether voluntary or involuntary;
(ii) if Tenant is a corporation, any dissolution, merger, consolidation or other
reorganization of Tenant, or the transfer, either by a single transaction or in
a series of transactions, of a controlling percentage of the stock of Tenant (except
that a Sublet shall not include any such transfer of a controlling percentage of
the stock of Tenant occurring at a time when the stock of Tenant is publicly traded
on a nationally recognized stock exchange or over the counter), or the sale, by
a single transaction of or series of transaction, within any one (1) year period,
of corporate assets equaling or exceeding twenty percent (20%) of the total value
of Tenant's assets (except in connection with an initial public offering of the
stock of Tenant on a nationally recognized stock exchange or over the counter);
(iii) if Tenant is a trust, the transfer, voluntarily or involuntarily, of all or
any part of the controlling interest in such trust; and (iv) if Tenant is any other
form of entity, a transfer, voluntary or involuntary, of all or any part of any
interest in such entity. As used herein, the phrases "controlling percentage" and
"controlling interest" means the ownership of, and/or the right to vote, stock,
partnership interests, membership interests, or other indicia of 
 
                                        8 

 ownership possessing at least fifty-one percent (51%) of either the total combined
interests in Tenant, or the voting power of all classes of Tenant's capital stock,
partnership interests, membership interests, or other indicia of ownership, that
have been issued, outstanding, and (if applicable) are entitled to vote.
 
           CC.  Subrent.  Any consideration of any kind received, or to be
                -------                                                    received,
by Tenant from a subtenant if such sums are related to Tenant's interest in this
Lease or in the Premises, including without limitation bonus money and payments
(in excess of book value) for Tenant's assets, including without limitation its
trade fixtures, equipment and other personal property, goodwill, general intangibles,
and any capital stock or other equity ownership of Tenant.
 
           DD.  Subtenant.  The person or entity with whom a Sublet agreement is
                ---------                        proposed to be or is made.
 
           EE.  Tenant Delay.  Any delay that Landlord may encounter in the
                ------------                                                performance
of Landlord's obligations under the Lease because of any act or omission of any
nature by Tenant or its agents or contractors, including without limitation any
(i) delay attributable to the postponement of any Improvements at the request of
Tenant; (ii) delay by Tenant in the submission of information or the giving of authorizations
or approvals within the time limits set forth in the Lease or the Work Letter; (iii)
delay attributable to the failure of Tenant to pay, when due, any amounts required
to be paid by Tenant pursuant to the Lease or the Work Letter; and (iv) delay resulting
from any change order request initiated or requested by Tenant.
 
           FF.  Tenant Improvements.  Those certain improvements to the Premises
                -------------------                                            
 to be constructed by Landlord pursuant to Exhibit B, other than the Capital
                                           ---------                         Improvements.
 The Tenant Improvements shall at all times be the property of Landlord and shall
not be deemed Tenant's Personal Property.
 
           GG.  Tenant's Percentage Share.  The ratio (expressed as a percentage)
                -------------------------                                      
  of the total Rentable Area of the Premises to the total Rentable Area of all of
the buildings at the Project owned by Landlord from time to time, which as of the
Commencement Date shall equal 47.3% (i.e., the Rentable Area of the Premises divided
by the Rentable Area of the buildings at the Project owned by Landlord as of the
date of this Lease).  Tenant's Percentage Share shall be recalculated each and every
time that the amount of Rentable Area contained in Premises is adjusted, or the
Premises is expanded, buildings are added to or removed from the Project, or there
is a change in the total Rentable Area of those buildings in the Project owned by
Landlord, or Landlord sells, exchanges, or otherwise transfers any or all of the
buildings situated in the Project (including without limitation the Building). 
The parties acknowledge and agree that the total Rentable Area of all of the buildings
in the Project owned by Landlord may increase and/or decrease from time to time
during the Term, since Landlord may elect in its sole discretion to sell a building
or buildings or to make changes to the buildings it owns in the Project (so long
as Landlord does not unreasonably interfere with ingress to or egress from the Premises).
 
           HH.  Tenant's Personal Property. Tenant's trade fixtures, furniture,
                --------------------------   equipment 
 
                                        9 

 and other personal property in the Premises.
 
           II.  Term.  The Term of this Lease set forth in Paragraph 4.A., as it
                ----                                       ------------- may be
extended hereunder pursuant to any options to extend granted herein.
 
           JJ.  Fixed Charge Ratio.  Tenant's consolidated earnings before income
                ------------------                                             
  taxes, depreciation and amortization during the fiscal year in question, divided
by the sum of (i) all interest charges occurring during the fiscal year in question,
and (ii) all of Tenant's scheduled debt amortization payable during the fiscal year
in question.
 
      4. Lease Term.
         ---------- 
 
           A.   Term.  Subject to adjustment for Tenant Delays pursuant to
                ----                                                       Paragraph
4.B below, the Term shall commence on the date of substantial completion of the
Improvements to be constructed by Landlord (the "Commencement
                                                                    ------------
Date"), and terminate on the date that is fifteen (15) years after the - ----  
                                                                Commencement Date.
 For the purposes of this Lease, substantial completion shall mean that the Improvements
have been completed in accordance with the Final Plans approved by Landlord and
Tenant, subject only to minor punch-list items, and the City of Redwood City has
issued a final building inspection approval for such Improvements.
 
           B.   Delays in Completion.  Tenant agrees that if Landlord, for any
                --------------------                                           reason
whatsoever, is unable to substantially complete the Improvements on or before Landlord's
initial estimate of the Commencement Date, Landlord shall not be liable to Tenant
for any loss or damage therefrom, nor shall this Lease be void or voidable.  Upon
the establishment of the actual Commencement Date, Landlord and Tenant shall execute
a Commencement Date Memorandum in the form set forth in Exhibit D.  Notwithstanding
any provision of this Lease to the
          ---------                                                      contrary,
if at any time after the date of this Lease a Tenant Delay occurs, then the Commencement
Date shall be moved earlier two (2) days for each one (1) day of Tenant Delay that
delays the substantial completion of the Improvements. In addition, Tenant shall
pay any and all costs and expenses incurred by Landlord which result from any Tenant
Delay, including, without limitation, any and all costs and expenses attributable
to increases in the cost of labor or materials.
 
           C.   Option to Extend.
                ---------------- 
 
                (i)  Grant of Option. Landlord hereby grants to Tenant one (1)
                     --------------- option (the "Option to Extend") to extend the
Term of this Lease, for an
              ---------------- additional term of five (5) years. The option term
(the "Extended Term") shall
                                                          ------------- commence
upon the expiration of the initial Term. The Option to Extend is expressly conditioned
upon Tenant's not being in default under any term or condition of this Lease after
the expiration of any applicable cure period granted by this Lease, either at the
time the Option to Extend is exercised or at the time the applicable Extended Term
would commence. The Option to Extend shall be personal to the Tenant originally
named in this Lease, and shall not be assigned, sold, conveyed or otherwise transferred
to any other party (including without limitation any assignee or sublessee of such
Tenant) without the prior written consent of Landlord, which consent may be withheld
in Landlord's sole discretion; provided, 
 
                                       10 

 however, that the Option to Extend may be transferred to the transferee pursuant
to a Permitted Transfer without Landlord's consent. The Option to Extend shall be
exercisable only so long as the Lease remains in full force and effect and shall
be an interest appurtenant to and not separable from Tenant's estate under the Lease.
Under no circumstances shall Landlord be required to pay any real estate commission
to any party with respect to Tenant's exercise of the Option to Extend.
 
                (ii)   Manner of Exercise.  Tenant may exercise the Option to
                       ------------------ Extend the Lease only by giving Landlord
written notice not less than one (1) year prior to the expiration of the Term. If
Tenant fails to exercise the Option to Extend prior to such 1-year period, then
the Option to Extend automatically shall lapse and thereafter Tenant shall have
no right to exercise the Option to Extend.
 
                (iii)  Terms and Rent.  The initial Monthly Rent for the Premises
                       -------------- for the Extended Term shall be equal to the
greater of (w) ninety-five percent (95%) of the fair market rent, as determined
below, for the Premises as of the commencement of the Extended Term, or (x) an amount
equal to the Monthly Rent payable during the fourteenth (14th) Lease Year of the
initial Term, multiplied by the greater of (A) the lesser of (I) a fraction, the
numerator of which is the Index published most recently before the first day of
the fourteenth (14th) Lease Year of the initial Term, and the denominator of which
is the Index published most recently before the first day of the thirteenth (13th)
Lease Year of the initial Term, or (II) one hundred sixteen percent (116%), or (B)
one hundred seven percent (107%). During the Extended Term the Monthly Rent shall
continue to be subject to adjustment in accordance with the provisions of Paragraph
5.B below.  All other terms and conditions of the Lease, as amended - -------------
                                                                from time to time
by the parties in accordance with the provisions of the Lease, shall remain in full
force and effect and shall apply during the Extended Term; provided, however, that
neither the Option to Extend nor Landlord's obligations under the Work Letter shall
be of any force or effect during the Extended Term.
 
                (iv)   Determination of Rent. For the purposes of calculating the
                       ---------------------  Monthly Rent for the Extended Term,
the fair market rent shall be equal to the net effective rent per rentable square
foot being charged for leases executed within the preceding twelve (12) months for
comparable space (in buildings with 2 - 4 stories) at either the Project (if any),
or if there are none, for comparable space (in buildings with 2 - 4 stories) in
office and research and development complexes located in the Redwood Shores area
or the Menlo Oaks Business Park (located in Menlo Park, California), with terms
comparable to the terms contained in this Lease, taking into consideration relevant
factors such as the presence or absence of tenant improvement contributions by the
lessor, and the fact that the Monthly Rent during the Extended Term shall be subject
to adjustment under Paragraph 5.B.  Any value added to the Premises by the Tenant
                  --------------                                               
Improvements and any Alterations paid for by Tenant shall not be considered or included
in the determination of the fair market rent.  The fair market rent shall be determined
by mutual agreement of the parties or, if the parties are unable to agree within
thirty (30) days after Tenant's exercise of an Option, then fair market rent shall
be determined pursuant to the procedure set forth in Paragraphs 4.C.(v) and 4.C.(vi).
- ------------------     -------- 
 
                (v)    Landlord's Initial Determination. If the parties are
                       --------------------------------  unable mutually to agree
upon the fair market rent pursuant to Paragraph
                                                                --------- 4.C.(iv),
then the fair market rent initially - --------
 
                                       11 

 shall be determined by Landlord by written notice ("Landlord's Notice") given to
                                                     ----------------- Tenant promptly
following the expiration of the 30-day period set forth in Paragraph 4.C.(iv). If
Tenant disputes the amount of fair market rent set forth - ------------------  
                                 in Landlord's Notice, then, within thirty (30)
days after the date of Landlord's Notice, Tenant shall send Landlord a written notice
("Tenant's Notice") which
                                                       --------------- specifically
(a) disputes the fair market rent set forth in Landlord's Notice, (b) demands arbitration
pursuant to Paragraph 4.C.(vi), and (c) states the name
                                     ------------------ and address of the person
who shall act as arbitrator on Tenant's behalf. Tenant's Notice shall be deemed
defective, and not given to Landlord, if it fails strictly to comply with the Requirements
and time period set forth above. If Tenant does not send Tenant's Notice within
thirty (30) days after the date of Landlord's Notice, or if Tenant's Notice fails
to contain all of the required information, then the Monthly Rent for the Extended
Term shall equal ninety-five percent (95%) of the fair market rent specified in
Landlord's Notice. If Tenant sends Tenant's Notice in the proper form within thirty
(30) days after the date of Landlord's Notice, then the Monthly Rent for the Extended
Term shall be determined by arbitration pursuant to Paragraph 4.C(vi) below. If
the
                                       ----------------- arbitration is not concluded
prior to the commencement of the Extended Term, then Tenant shall pay Monthly Rent
equal to one hundred twenty-five percent (125%) of the Monthly Rent payable immediately
prior to the commencement of the Extended Term. If the fair market rent determined
by arbitration differs from that paid by Tenant pending the results of arbitration,
then any adjustment required to adjust the amount previously paid shall be made
by payment by the appropriate party within ten (10) days after the determination
of fair market rent.
 
                (vi)   Arbitration.  The arbitration shall be conducted in the
                       ----------- City of San Francisco in accordance with the
then prevailing rules of the American Arbitration Association (or its successor)
for the arbitration of commercial disputes, except that the procedures mandated
by such rules shall be modified as follows:
 
                          (a)  Each arbitrator must be a real estate appraiser with
at least five (5) years of full-time commercial appraisal experience who is familiar
with the fair market rent of office and research and development complexes located
in the vicinity of the Premises. Within ten (10) business days after receipt of
Tenant's Notice, Landlord shall notify Tenant of the name and address of the person
designated by Landlord to act as arbitrator on Landlord's behalf.
 
                          (b)  The two arbitrators chosen pursuant to Paragraph
                                                                      ---------
4.C.(vi)(a) shall meet within ten (10) business days after the second arbitrator
- ----------- is appointed and shall either agree upon the fair market rent or appoint
a third arbitrator possessing the qualifications set forth in Paragraph 4.C.(vi)(a).
If
                                                       ---------------------   
  the two arbitrators agree upon the fair market rent within such ten (10) business
day period, the Monthly Rent for the Extended Term shall equal ninety- five percent
(95%) of such fair market rent. If the two arbitrators are unable to agree upon
the fair market rent and are unable to agree upon the third arbitrator within five
(5) business days after the expiration of such ten (10) business day period, the
third arbitrator shall be selected by the parties themselves.  If the parties do
not agree on the third arbitrator within five (5) business days after the expiration
of such five (5) business day period, then either party, on behalf of both, may
request appointment of the third arbitrator by the Association of South say Brokers.
The three arbitrators shall decide the dispute, if it has not been previously resolved,
by following the procedures set forth in Paragraph 4.C.(vi)(c).  Each party shall
pay the fees and expenses of
          ---------------------                                                
its 
 
                                       12 

 respective arbitrator and both shall share the fees and expenses of the third arbitrator.
Each party shall pay its own attorneys' fees and costs of witnesses.
 
                          (c)  The three arbitrators shall determine the fair market
rent in accordance with the following procedures. Each of Landlord's arbitrator
and Tenant's arbitrator shall state, in writing, his or her determination of the
fair market rent, supported by the reasons therefor, and shall make counterpart
copies for the other arbitrators. All of the arbitrators shall arrange for a simultaneous
exchange of the proposed resolutions within ten (10) business days after appointment
of the third arbitrator. If any arbitrator fails to deliver his or her own determination
to the other arbitrators within such ten (10) business day period, then the fair
market rent shall equal the average of the resolutions submitted by the other arbitrators.
If all three (3) arbitrators deliver their determinations to the other arbitrators
within such ten (10) business day period, then the two (2) closest determinations
of the arbitrators shall be averaged, and the resulting quotient shall be the fair
market rent, and the Monthly Rent for the Extended Term shall equal ninety-five
percent (95%) of such fair market rent; provided, however, that if the determination
of one (1) of the arbitrators (the "Average Determination") is
                                                   --------------------- equal to
the average of the determinations of the other two (2) arbitrators, then the Average
Determination shall be the fair market rent. However, the arbitrators shall not
attempt to reach a mutual agreement of the fair market rent; each arbitrator shall
independently arrive at his or her proposed resolution.
 
                          (d)  The arbitrators shall have the right to consult experts
and competent authorities for factual information or evidence pertaining to a determination
of fair market rent, but any such consultation shall be made in the presence of
both parties with full right on their part to cross-examine. The arbitrators shall
render the decision and award in writing with counterpart copies to each party.
The arbitrators shall have no power to modify the provisions of this Lease. In the
event of a failure, refusal or inability of any arbitrator to act, his or her successor
shall be appointed by him or her, but in the case of the third arbitrator, his or
her successor shall be appointed in the same manner as that set forth herein with
respect to the appointment of the original third arbitrator.
 
      5.   Rent and Additional Charges.
           --------------------------- 
 
           A.  Monthly Rent.  Tenant shall pay to Landlord, in lawful money of
               ------------                                                    the
United States, Monthly Rent as follows: commencing on the Commencement Date, and
continuing through the balance of the Term (subject to adjustment pursuant to Paragraph
5.B), the initial Monthly Rent shall equal that amount calculated
    -------------                                                              
pursuant to the Build to Suit Agreement as the Monthly Rent for the Building. Tenant
shall have no obligation to pay Monthly Rent before the Commencement Date.  Until
the Monthly Rent is established under the Build to Suit Agreement, the Monthly Rent
shall be deemed to equal that amount designated from time to time in writing by
Landlord to Tenant as Landlord's reasonable estimate of the amount of Monthly Rent
that will be established under the Build to Suit Agreement upon completion of the
construction of the Building (collectively, the "Estimated Monthly Rent"), based
upon Landlord's estimate of the Development  ----------------------            
                                         Costs (as defined in the Build to Suit
Agreement) that have been or will be incurred in constructing the Building.  Upon
the final establishment of the initial Monthly 
 
                                       13 

 Rent in accordance with the Build to Suit Agreement, Landlord and Tenant shall
each execute an addendum to this Lease setting forth the initial Monthly Rent under
this Lease. If as of the date the initial Monthly Rent under this Lease is established
(the "Rent Establishment Date"), the aggregate amount of Estimated
                   -----------------------        Monthly Rent previously paid by
Tenant exceeds the aggregate amount of Monthly Rent payable under this Lease from
the Commencement Date to the Rent Establishment Date, then Landlord may elect, in
its sole discretion, to either refund such excess to Tenant within thirty (30) days
after the Rent Establishment Date, or offset such overpayment against Rent due or
remaining due under this Lease. If as of the Rent Establishment Date the aggregate
amount of Estimated Monthly Rent previously paid by Tenant is less than the aggregate
amount of Monthly Rent payable under this Lease from the Commencement Date to the
Rent Establishment Date, then Tenant shall pay the deficiency to Landlord within
thirty (30) days after the Rent Establishment Date.
 
           Monthly Rent shall be paid in advance, on the first day of each calendar
month during the Term, without abatement, deduction, claim, offset, prior notice
or demand. Tenant shall pay to Landlord an amount equal to one (1) month's advance
payment of Monthly Rent for the Premises upon the execution of this Lease by Landlord
and Tenant.  Additionally, Tenant shall pay, as and with the Monthly Rent, the management
fee described in Paragraph 5.C., Tenant's
                                                   --------------           Percentage
Share of Common Area Maintenance Costs pursuant to Paragraph 5.D, the
                                                               -------------   
  Real Property Taxes and Impositions payable by Tenant pursuant to Paragraph 15,
                                                                   ------------
 and the monthly cost of insurance premiums required pursuant to Paragraph 21.C.
                                                                 --------------

 
           B.  Adjustments to Monthly Rent.  The Monthly Rent may be adjusted at
               ---------------------------                                     
 any time during the Term in accordance with the provisions of Paragraph 2.1.1 of
                                                               --------------- 
  Exhibit D to the Build to Suit Agreement.  In addition, the Monthly Rent shall
- ---------                                                                    
 be increased, but not decreased, as of the first day of the month which is twenty-five
(25) months from the Commencement Date and every twenty-four (24) months thereafter
during the Term (including without limitation the Extended Term) (each, an "Adjustment
Date") by the greater of (i) the percentage increase
                  ---------------                                              
  in the Index from the previous Adjustment Date (or, for the first Adjustment Date,
from the Commencement Date), up to a maximum of sixteen percent (16%), or (ii) seven
percent (7%).  If, however, the last Adjustment Date occurs at any time after the
first day of a calendar month, the first Adjustment Date shall be the first day
of the immediately following calendar month.  On each Adjustment Date, the total
aggregate amount of Monthly Rent then in effect shall be multiplied by the greater
of (x) the lesser of (A) a fraction, the numerator of which is the Index published
most recently before the applicable Adjustment Date, and the denominator of which
is the Index published most recently before the prior Adjustment Date (or, in the
case of the first Adjustment Date, the Index published most recently before the
Commencement Date), or (B) one hundred sixteen percent (116%), or (y) one hundred
seven percent (107%); and the corresponding product shall be the Monthly Rent in
effect until the next Adjustment Date.  In no event shall the Monthly Rent in effect
after an Adjustment Date be less than one hundred seven percent (107%) of the Monthly
Rent in effect immediately prior to such Adjustment Date.  If no Index is published
for either of the months set forth above, the Index for the next preceding month
shall be used.
 
           C.  Management Fee.  Tenant shall pay to Landlord monthly, as
               --------------                                            Additional

 
                                       14 

 Rent, a management fee equal to three and one-half percent (3.5%) of the then Monthly
Rent.
 
           D.   Common Area Maintenance Costs.
                ----------------------------- 
 
                (i)    Estimated Payments. Commencing on the Commencement Date
                       ------------------ and continuing throughout the entire Term,
Tenant shall pay Tenant's Percentage Share of all Common Area Maintenance Costs
paid or payable by Landlord in each year; provided, however, that Tenant shall pay
one hundred percent (100%) of those Common Area Maintenance Costs arising from Landlord's
performance of its obligations under Paragraphs 17.A and Tenant's obligations under
Paragraph 17.D.
                   ---------------                                --------------
Before commencement of the Term and during December of each calendar year or as
soon thereafter as practicable, Landlord shall give Tenant notice of its estimate
of amounts payable under this Paragraph 5.D.(i) for the ensuing
                                        -----------------                 calendar
year.  Such notice shall show in reasonable detail the basis on which the estimate
was determined.  On or before the first day of each month during the ensuing calendar
year, Tenant shall pay to Landlord one-twelfth (1/12th) of such estimated amounts,
provided that if such notice is not given in December, Tenant shall continue to
pay on the basis of the prior year's estimate until the month after such notice
is given.  If at any time or times it appears to Landlord, in its reasonable judgment,
that the amounts payable under this Paragraph 5.D.(i) for the current calendar year
will vary from its then-current - -----------------                            
                                  estimate by more than five percent (5%), Landlord
may, in its sole discretion, by notice to Tenant, showing in reasonable detail the
basis for such variance, revise its estimate for such year, in which case subsequent
payments by Tenant for such year shall be based upon such revised estimate.  Landlord's
election not to give the notice described in the foregoing sentence shall not affect
Landlord's ability to charge Tenant for, nor Tenant's liability to pay for, any
shortfall in the estimated payments for such calendar year previously made by Tenant,
as set forth in Paragraph 5.D.(ii).
                         ------------------ 
 
                (ii)   Adjustment. Within one hundred twenty (120) days after the
                       ----------  close of each calendar year or as soon after
such 120-day period as reasonably practicable, Landlord shall deliver to Tenant
a reasonably detailed statement of Common Area Maintenance Costs for such calendar
year, certified by Landlord or its property manager, subject to Tenant's right to
audit as hereinafter provided.  At that time, Landlord shall also deliver to Tenant
a statement, certified as correct by Landlord, of the adjustments to be made pursuant
to Paragraph 5.D.(i) above. If Landlord's statement shows that Tenant owes an -
-----------------                                                          amount
that is less than the estimated payments for such calendar year previously made
by Tenant, Landlord may elect, in its sole discretion, to either refund such excess
to Tenant within thirty (30) days after delivery of the statement, or offset such
overpayment against Rent due or remaining due under this Lease; provided that if
no Rent remains due, Landlord shall refund such excess to Tenant within thirty (30)
days after delivery of the statement.  If such statement shows that Tenant owes
an amount that is more than the estimated payments for such calendar year previously
made by Tenant, Tenant shall pay the deficiency to Landlord within thirty (30) days
after delivery of the statement.
 
                (iii)  Last Year.  If this Lease shall terminate on a day other
                       --------- than the last day of a calendar year, the adjustment
in Rent applicable to the calendar year in which such termination shall occur shall
be prorated on the basis which the number of days from the commencement of such
calendar year to and including such termination date bears to three 
 
                                       15 

 hundred sixty (360). The termination of this Lease shall not affect the obligations
of Landlord and Tenant pursuant to Paragraph 5.D.(ii) to be
                                                ------------------ performed after
such termination.
 
                (iv)   Audit. Within one hundred eighty (180) days after receipt
                       ----- of Landlord's statement of Common Area Maintenance
Costs as provided in Paragraph 5.D.(ii), Tenant or its designee, on not less than
five (5) days' - ------------------ prior written notice to Landlord, shall have
the right to, at Tenant's sole cost and expense, audit, examine and copy Landlord's
books and records with respect to the Common Area Maintenance Costs for the calendar
year pertaining to the year for which the Landlord's statement pertains. Landlord
shall cooperate with Tenant in any such examination of its books and records.
 
           E.   Additional Rent.  All monies required to be paid by Tenant under
                ---------------                                                
 this Lease, including, without limitation, the Tenant Improvement costs pursuant
to Exhibit B, the management fee described in Paragraph 5.D, Tenant's Percentage
    ---------                                  -------------                   
  Share of Common Area Maintenance Costs pursuant to Paragraph 5.D, Real Property
                                                    -------------              
 Taxes and Impositions pursuant to Paragraph 15, and the monthly cost of
                                   ------------                          insurance
premiums required pursuant to Paragraph 21.C, shall be deemed
                                         --------------                  Additional
Rent.
 
           F.   Prorations.  If the Commencement Date or the Second Half
                ----------                                               Commencement
Date is not the first (1st) day of a month, or if the termination date of this Lease
is not the last day of a month, a prorated installment of Monthly Rent based on
a 30-day month shall be paid for the fractional month during which such date occurs
or the Lease terminates.
 
           G.   Interest.  Any amount of Rent or other charges provided for under
                --------                                                       
  this Lease due and payable to Landlord which is not paid when due shall bear interest
at the Interest Rate from the date that is (i) five (5) days after the date such
Rent is due until such Rent is paid, or (ii) ten (10) days after Tenant receives
written notice from Landlord that any other charge provided for under this Lease
(other than Rent) is due and payable, until such other charge is paid.
 
      6.   Late Payment Charges.
           -------------------- 
 
           Tenant acknowledges that late payment by Tenant to Landlord of Rent and
other charges provided for under this Lease will cause Landlord to incur costs not
contemplated by this Lease, the exact amount of such costs being extremely difficult
or impracticable to fix.  Therefore, if any installment of Rent or any other charge
due from Tenant (excluding late release of the Set- Aside Funds pursuant to the
Work Letter) is not received by Landlord within three (3) days after the date such
Rent or other charge is due, Tenant shall pay to Landlord an additional sum equal
to seven percent (7%) of the amount overdue as a late charge for every month or
portion thereof that the Rent or other charges remain unpaid.  The parties agree
that this late charge represents a fair and reasonable estimate of the costs that
Landlord will incur by reason of the late payment by Tenant.

 Initials:
 
                                       16 

 /s/ C. G.                                /s/ K. A. G. - ------------------------
                ------------------------- Landlord                             
   Tenant
 
      7.   Security Deposit.
           ---------------- 
 
           A.   Deposit Required.  Tenant shall deposit with Landlord upon the
                ----------------                                               execution
of this Lease by Landlord and Tenant, an amount equal to three (3) payments of the
Estimated Monthly Rent under this Lease, as the "Security
                                                                  -------- Deposit"
for the full and faithful performance of every provision of this Lease - -------
                                                                        to be performed
by Tenant.  Effective as of the Rent Establishment Date, the Security Deposit shall
be adjusted (if necessary) to equal three (3) payments of the initial Monthly Rent
under this Lease. If as of the Rent Establishment Date the Estimated Monthly Rent
exceeds the initial Monthly Rent as determined under Paragraph 5.A above, then Landlord
shall refund to Tenant, within thirty (30) - -------------                     
                                           days after the Rent Establishment Date,
any overpayment of the Security Deposit. If as of the Rent Establishment Date the
Estimated Monthly Rent is less than the initial Monthly Rent as determined under
Paragraph 5.A above, then Tenant shall
                                          -------------                        
 increase the Security Deposit by paying the deficiency in the Security Deposit
to Landlord within thirty (30) days after the Rent Establishment Date.  For the
purposes of this Lease, the term "Security Deposit" shall include the initial sum
deposited by Tenant as the Security Deposit and any other sum deposited by Tenant
as the Security Deposit and any other sum deposited by Tenant towards the Security
Deposit pursuant to this Paragraph 7.A.  At Tenant's option, the
                                   -------------                           Security
Deposit may be in the form of an irrevocable standby letter of credit ("L-C"). Landlord
shall not be required to segregate the Security Deposit from Landlord's general
funds; Landlord's obligations with respect to the Security Deposit shall be those
of a debtor and not a trustee, and Tenant shall not be entitled to any interest
on the Security Deposit.  Invocation by Landlord of its rights hereunder shall not
constitute a waiver of nor relieve Tenant from any liability or obligation for any
default by Tenant under this Lease.
 
                (i)  Reduction or Replacement. So long as Tenant has not
                     ------------------------ committed any default under this Lease,
then if Tenant can demonstrate to the reasonable satisfaction of Landlord that Tenant
has maintained a Fixed Charge Ratio of at least 1.25 to 1 for a period of four (4)
consecutive fiscal years at any time after the Commencement Date, then Tenant may
elect to reduce the Security Deposit to a sum equal to the then-current amount of
Monthly Rent. For the purposes of this Paragraph 7, in order for Tenant to demonstrate
that it has
                      -----------                                              
  maintained the required Fixed Charge Ratio for the fiscal year or years in question,
Tenant must at a minimum deliver to Landlord an audited financial statement of Tenant,
showing that Tenant has maintained the required Fixed Charge Ratio for the fiscal
year or years in question.
 
           If Tenant is entitled to and does elect to reduce the amount of the Security
Deposit pursuant to this Paragraph 7.A.(i), and Tenant delivers to
                                   -----------------                         Landlord
written notice of its election to so reduce the amount of the Security Deposit and
the financial statement described in the foregoing grammatical paragraph, then either
(x) if the Security Deposit is in the form of cash, Landlord shall pay to Tenant
the excess amount of the Security Deposit, without interest, within thirty (30)
days after Landlord's receipt of such notice and statement; or (y) if the Security
Deposit is in the form of an L-C, then Tenant may, not less than ten (10) days after
Landlord's receipt of such notice and statement, replace the L-C with an L-C in
an amount equal to the 
 
                                       17 

 reduced amount of the Security Deposit.
 
                (ii)   Consequences of Default. If Tenant defaults with respect
                       ----------------------- to any provision of this Lease, after
the expiration of any applicable cure or grace periods expressly provided for in
this Lease, Landlord may apply all or any part of the Security Deposit for the payment
of any Rent or other sum in default, the repair of such damage to the Premises or
the payment of any other amount which Landlord may spend or become obligated to
spend by reason of Tenant's default or to compensate Landlord for any other loss
or damage which Landlord may suffer by reason of Tenant's default to the full extent
permitted by law. If any portion of a cash Security Deposit is so applied, or any
portion of an L-C posted as the Security Deposit, if applicable, is drawn upon,
by Landlord for such purposes, Tenant shall either, within ten (10) days after written
demand therefor, deposit cash with Landlord in an amount sufficient to restore the
Security Deposit to its original amount or deposit a replacement L-C with Landlord
in the amount of the original L-C. If Tenant is not otherwise in default, the Security
Deposit or any balance thereof shall be returned to Tenant within thirty (30) days
of termination of the Lease.
 
                (ii)   Form of L-C. If at any time Tenant elects to deposit an L-
                       ----------- C as the Security Deposit, the L-C shall be issued
by a bank reasonably acceptable to Landlord, shall be issued for a term of at least
twelve (12) months and shall be in a form and with such content reasonably acceptable
to Landlord. Tenant shall either replace the expiring L-C with an L-C in an amount
equal to the original L-C or renew the expiring L-C, in any event no later than
thirty (30) days prior to the expiration of the term of the L-C then in effect.
If Tenant fails to deposit a replacement L-C or renew the expiring L-C, Landlord
shall have the right to draw upon the expiring L-C for the full amount thereof and
hold the same as the Security Deposit; provided, however, that if Tenant provides
a replacement L-C that meets the requirements of this Paragraph, then Landlord shall
return to Tenant promptly in cash that amount of the L-C that had been drawn upon
by Landlord. Drawing upon the L-C shall be conditioned upon the presentation to
the issuer of the L-C of a certified statement executed by a general partner of
Landlord that (i) Tenant is in default under the Lease and Landlord is exercising
its right to draw upon so much of the L-C as is necessary to cure Tenant's default,
or (ii) Tenant has not renewed or replaced an expiring L-C as required by this Lease
and Landlord is authorized to draw upon the L-C prior to its expiration. The L-C
shall not be mortgaged, assigned or encumbered in any manner whatsoever by Tenant
without the prior written consent of Landlord. The use, application or retention
of the L-C, or any portion thereof, by Landlord shall not prevent Landlord from
exercising any other right or remedy provided by this Lease or by law, it being
intended that Landlord shall not first be required to proceed against the L-C, and
such use, application or retention shall not operate as a limitation on any recovery
to which Landlord may otherwise be entitled.
 
      8.   Holding Over.
           ------------ 
 
           If Tenant remains in possession of all or any part of the Premises after
the expiration of the Term, with the express or implied consent of Landlord, such
tenancy shall be at sufferance only, and shall not constitute a renewal or extension
for any further term.  If Tenant 
 
                                       18 

 remains in possession after the expiration of the Term, either with or without
Landlord's consent, Rent shall be payable at a rental equal to one hundred thirty
percent (130%) of the Monthly Rent payable during the last month of the Term (which
rental shall be due and payable at the same time as Monthly Rent is due under this
Lease), and any other sums due under this Lease shall be payable in the amount and
at the times specified in this Lease. Such holdover tenancy shall be subject to
every other term, condition, and covenant contained herein; provided, however, that
neither the Holdover Option (as defined below) nor Landlord's obligations under
the Work Letter shall be of any force or effect during any such holdover tenancy.
 
      9.   Tenant Improvements.
           ------------------- 
 
           Landlord agrees to construct the Tenant Improvements pursuant to the
terms of Exhibit B.
          --------- 
 
      10.  Condition of Premises.
           --------------------- 
 
           A.   Capital Improvements.  Landlord shall complete the Capital
                --------------------                                       Improvements
in accordance with the terms of Exhibit B; provided, however, that
                                              ---------                        
 the construction of the shell and core of the Building shall be governed by the
terms of the Build to Suit Agreement.  Except for its obligation to perform the
Capital Improvements and the Tenant Improvements as set forth in this Lease and
the Work Letter, Landlord shall have no obligation whatsoever to do any work or
perform any improvements whatsoever to any portion of the Premises or the Building.
 
           B.   Acceptance of Premises.  Within ten (10) days after completion of
                ----------------------                                         
  the Tenant Improvements Tenant shall conduct a walk-through inspection of the
Premises with Landlord and complete a punch list of items needing additional work.
 Other than the items specified in the punch list, if any, and subject to Landlord's
representations and warranties described below, by taking possession of the Premises,
Tenant shall be deemed to have accepted the Premises in good, clean and completed
condition and repair, subject to all applicable laws, codes and ordinances.  Any
damage to the Premises caused by Tenant's move-in shall be repaired or corrected
by Tenant, at its sole cost and expense, which repair or corrective work shall not
be paid for out of the Tenant Improvements Allowance. Tenant acknowledges that neither
Landlord nor Landlord's Agents have made any representations or warranties as to
the suitability or fitness of the Premises for the conduct of Tenant's business
or for any other purpose, nor has Landlord or Landlord's Agents agreed to undertake
any Alterations or construct any Improvements to the Premises except as expressly
provided in this Lease.  If Tenant fails to submit a punch-list to Landlord within
such 10-day period, it shall be deemed that there are no Improvement items needing
additional work or repair.  Landlord's contractor shall complete all reasonable
punch-list items within thirty (30) days after the walk-through inspection or as
soon as practicable thereafter. Upon completion of such punch-list items, Tenant
shall approve such completed items in writing to Landlord.  If Tenant fails to approve
such items within fourteen (14) days of completion, such items shall be deemed approved
by Tenant.
 
      11.  Use of the Premises and Common Area.
           ----------------------------------- 
 
                                       19 
 
           A.   Tenant's Use.  Tenant shall use the Premises only for general
                ------------                                                  office,
research and development, marketing, sales, and storage related to such activities,
and any other legal use consistent with any CC&Rs.  Tenant shall not use the Premises
or suffer or permit anything to be done in or about the Premises which will in any
way conflict with any law, statute, zoning restriction, ordinance or governmental
law, rule, regulation or requirement of public authorities now in force or which
may hereafter be in force, relating to or affecting the condition, use or occupancy
of the Premises.  Tenant shall not commit any public or private nuisance or any
other act or thing which might or would disturb the quiet enjoyment of any other
tenant of Landlord or any occupant of nearby property.  Tenant shall place no loads
upon the floors, walls or ceilings in excess of the maximum designed load determined
by a licensed structural engineer or which endanger the structure; nor place any
harmful liquids in the drainage systems; nor dump or store waste materials or refuse
or allow waste materials or refuse to remain outside the Building proper, except
in the enclosed trash areas provided.  Tenant shall not store or permit to be stored
or otherwise placed any other material of any nature whatsoever outside the Building,
except on a temporary basis.
 
           B.   Hazardous Materials.
                ------------------- 
 
                (i)    Hazardous Materials Defined. As used herein, the term
                       --------------------------- "Hazardous Materials" shall mean
any wastes, materials or substances (whether in  ------------------ the form of
liquids, solids or gases, and whether or not air-borne), which are or are deemed
to be (a) pollutants or contaminants, or which are or are deemed to be hazardous,
toxic, ignitable, reactive, corrosive, dangerous, harmful or injurious, or which
present a risk to public health or to the environment, or which are or may become
regulated by or under the authority of any applicable local, state or federal laws,
judgments, ordinances, orders, rules, regulations, codes or other governmental restrictions,
guidelines or requirements, any amendments or successor(s) thereto, replacements
thereof or publications promulgated pursuant thereto, including, without limitation,
any such items or substances which are or may become regulated by any of the Environmental
Laws (as hereinafter defined); (b) listed as a chemical known to the State of California
to cause cancer or reproductive toxicity pursuant to Section 25249.8 of the California
Health and Safety Code, Division 20, Chapter 6.6 (Safe Drinking Water and Toxic
Enforcement Act of 1986); or (c) a pesticide, petroleum, including crude oil or
any fraction thereof, asbestos or any  asbestos-containing material, a polychlorinated
biphenyl, radioactive material, or urea formaldehyde.
 
                (ii)   Environmental Laws Defined.  In addition to the laws 
                       --------------------------  referred to in Paragraph 11.B.(i)
above, the term "Environmental Laws" shall be
                ------------------                  ------------------ deemed to
include, without limitation, 33 U.S.C. Section 1251 et seq., 42 
                                                     ------                    
U.S.C. Section 6901 et seq., 42 U.S.C. Section 7401 et seq., 42 U.S.C. 
                     ------                          ------  Section 9601 et seq.,
and California Health and Safety Code Section 25100 et 
              ------                                                       -- seq.,
and 25300 et seq., California Water Code, Section 13020 et seq., or any  - --- 
           ------                                        ------ successor(s) thereto,
all local, state and federal laws, judgments, ordinances, orders, rules, regulations,
codes and other governmental restrictions, guidelines and requirements, any amendments
and successors thereto, replacements thereof and publications promulgated pursuant
thereto, which deal with or otherwise in any manner relate to, air or water quality,
air emissions, soil or ground conditions or other environmental matters of any kind.
 
                                       20 
 
                (iii)  Use of Hazardous Materials. Tenant agrees that during the
                       --------------------------  Term of this Lease, Tenant shall
not use, or permit the use of, nor store, generate, treat, manufacture or dispose
of Hazardous Materials on, from or under the Premises (individually and collectively,
"Hazardous Use") except to the
                                               -------------  extent that, and in
accordance with such conditions as, Landlord may have previously approved in writing
in its sole and absolute discretion. Notwithstanding the foregoing, Tenant shall
be entitled to use and store only those Hazardous Materials which are (a) set forth
in a list prepared by Tenant and approved in writing by Landlord, which shall be
deemed given with respect to the Approved Hazardous Materials (hereinafter defined),
(b) necessary for Tenant's business, but then only in the amounts and for the purposes
previously disclosed in writing to and approved in writing by Landlord, and (c)
in full compliance with Environmental Laws, and all judicial and administrative
decisions pertaining thereto. All Hazardous Materials approved in writing by Landlord
as provided in the preceding sentence shall collectively be referred to as the "Approved
Hazardous Materials". Within thirty (30) days after request by
         ---------------------------- Landlord, Tenant shall deliver to Landlord
a list of the Approved Hazardous Materials. Tenant shall not be entitled to install
any tanks under, on or about the Premises for the storage of Hazardous Materials
without the express written consent of Landlord, which may be given or withheld
in Landlord's sole discretion. For the purposes of this Paragraph 11.B.(iii), the
term Hazardous
                                      -------------------- Use shall include Hazardous
Use(s) on, from or under the Premises by Tenant, any Subtenant occupying all or
any portion of the Premises during the Term, or any of their directors, officers,
employees, shareholders, partners, invitees, agents, contractors or occupants (collectively,
"Tenants Parties"), whether
                                                  --------------- known or unknown
to Tenant, occurring during the Term of this Lease. The term "Tenant's Parties"
shall not include any tenants of the Project other than  ---------------- Tenant,
except that the term "Tenant's Parties" shall include any Subtenant occupying all
or any portion of the Premises during the Term.
 
                (iv)   Hazardous Materials Report; When Required. Tenant shall
                       ----------------------------------------- submit to Landlord
a written report with respect to Hazardous Materials ("Report") in the form prescribed
in Paragraph 11.B.(v) below on the following   ------                          
  ------------------ dates:
 
                         (a)  At any time within ten (10) days after written request
by Landlord, and
 
                         (b)  At any time when there has been a violation of any
Environmental Law, or in connection with any proposed request for Landlord's consent
to any change in the list of Approved Hazardous Materials or for an increase in
the intensity of usage or storage of such Approved Hazardous Materials.
 
                (v)    Hazardous Materials Report; Contents. The Report shall
                       ------------------------------------ contain, without limitation,
the following information:
 
                       (a)  Whether on the date of the Report and (if applicable)
during the period since the last Report there has been any Hazardous Use on, from
or under the Premises, other than the use of Approved Hazardous Materials.
 
                       (b)  If there was such Hazardous Use, the exact identity
of the 
 
                                       21 

 Hazardous Materials (other than the Approved Hazardous Materials), the dates upon
which such materials were brought upon the Premises, the dates upon which such Hazardous
Materials were removed therefrom, and the quantity, location, use and purpose thereof.
 
                       (c)  If there was such Hazardous Use, any governmental permits
maintained by Tenant with respect to such Hazardous Materials, the issuing agency,
original date of issue, renewal dates (if any) and expiration date. Copies of any
such permits and applications therefor shall be attached.
 
                       (d)  If there was such Hazardous Use, any governmental reporting
or inspection requirements with respect to such Hazardous Materials, the governmental
agency to which reports are made and/or which conducts inspections, and the dates
of all such reports and/or inspections (if applicable) since the last Report. Copies
of any such Reports shall be attached.
 
                       (e)  If there was such Hazardous Use, identification of any
operation or business plan prepared for any government agency with respect to Hazardous
Use.
 
                       (f)  Any liability insurance carried by Tenant with respect
to Hazardous Materials, if any, the insurer, policy number, date of issue, coverage
amounts, and date of expiration. Copies of any such policies or certificates of
coverage shall be attached.
 
                       (g)  Any notices of violation of Environmental Laws, written
or oral, received by Tenant from any governmental agency since the last Report,
the date, name of agency, and description of violation. Copies of any such written
notices shall be attached.
 
                       (h)  Any knowledge, information or communication which Tenant
has acquired or received relating to (x) any enforcement, cleanup, removal or other
governmental or regulatory action threatened or commenced against Tenant or with
respect to the Premises pursuant to any Environmental Laws; (y) any claim made or
threatened by any person or entity against Tenant or the Premises on account of
any alleged loss or injury claimed to result from any alleged Hazardous Use on or
about the Premises; or (z) any report, notice or complaint made to or filed with
any governmental agency concerning any Hazardous Use on or about the Premises. The
Report shall be accompanied by copies of any such claim, report, complaint, notice,
warning or other communication that is in the possession of or is available to Tenant.
 
                       (i)  Such other pertinent information or documents as are
reasonably requested by Landlord in writing.
 
                (vi)  Release of Hazardous Materials; Notification and Cleanup.
                      -------------------------------------------------------- 
 
                       (a)  At any time during the Term, if Tenant knows or believes
that any release of any Hazardous Materials has come or will come to be located
upon, about or beneath the Premises, then Tenant shall immediately, either prior
to the release or following the discovery thereof by Tenant, give verbal and follow-up
written notice of that condition to 
 
                                       22 

 Landlord.
 
                       (b)  At its sole cost and expense, Tenant covenants to investigate,
clean up and otherwise remediate any release of Hazardous Materials which were caused
or created by Tenant or any of Tenant's Parties. Such investigation, clean-up and
remediation shall be performed only after Tenant has obtained, if practicable, Landlord's
written consent, which shall not be unreasonably withheld; provided, however, that
Tenant shall be entitled to respond immediately to an emergency without first obtaining
Landlord's written consent. All clean-up and remediation shall be done in compliance
with Environmental Laws and to the reasonable satisfaction of Landlord.
 
                       (c)  Notwithstanding the foregoing, Landlord shall have the
right, but not the obligation, in Landlord's sole and absolute discretion, exercisable
by written notice to Tenant, to undertake within or outside the Premises all or
any portion of any reasonable investigation, clean-up or remediation with respect
to any Hazardous Use of such Hazardous Materials by Tenant or any of Tenant's Parties
(or, once having undertaken any of such work, to cease same, in which case Tenant
shall perform the work), all at Tenant's sole cost and expense, which shall be paid
by Tenant as Additional Rent within ten (10) days after receipt of written request
therefor by Landlord (and which Landlord may require to be paid prior to commencement
of any work by Landlord); provided, however, that Tenant's obligation to pay for
such work shall only be applicable if Tenant fails to perform its obligations under
this Paragraph 11
                                                                  ------------ (including
without limitation the obligations described in Paragraph
                                                            --------- 11.B.(vi)(b)).
No such work by Landlord shall create any liability on the part - -------------
of Landlord to Tenant or any other party in connection with such Hazardous Materials
by Tenant or any of Tenant's Parties or constitute an admission by Landlord of any
responsibility with respect to such Hazardous Materials.
 
                       (d)  It is the express intention of the parties hereto
                            -------------------                            that
Tenant shall be liable under this Paragraph 11.B.(vi) for any and all conditions
covered hereby which were or are caused or created by Tenant or any of Tenant's
Parties, whether occurring prior to, on, or after the Commencement Date. Tenant
shall not enter into any settlement agreement, consent decree or other compromise
with respect to any claims relating to any Hazardous Materials in any way connected
to the Premises without first (x) notifying Landlord of Tenant's intention to do
so and affording Landlord the opportunity to participate in any such proceedings,
and (y) obtaining Landlord's written consent, which shall not be unreasonably withheld.
 
                (vii)  Inspection and Testing by Landlord. Landlord shall have
                       ----------------------------------  the right at all times
during the Term of this Lease to (a) inspect the Premises, as well as such of Tenant's
books and records pertaining to the Premises and the conduct of Tenant's business
therein, and to (b) conduct tests and investigations to determine whether Tenant
is in compliance with the provisions of this Paragraph 11.B. Except in case of emergency,
Landlord shall
                    -------------- give reasonable notice to Tenant before conducting
any inspections, tests, or investigations in accordance with Paragraph 19, shall
provide Tenant with a work
                                   ------------                                
  plan describing any testing that shall be performed at the Premises, and shall
use reasonable efforts to minimize interference with the conduct of Tenant's business
at the Premises caused by any such inspections, tests, or investigations. The cost
of all such inspections, tests and investigations shall be borne by Tenant.  
 
                                       23 

 Neither any action nor inaction on the part of Landlord pursuant to this Paragraph
11.B.(vii) shall be deemed in any way to release Tenant from, or in - --------------------
                                      any way modify or alter, Tenant's responsibilities,
obligations, and liabilities incurred pursuant to Paragraph 11.B hereof.
                      --------------        
 
                (viii)  Indemnity.  Tenant shall indemnify, defend, protect, hold
                        ---------                                              
  harmless, and, at Landlord's option (with such attorneys as Landlord may approve
in advance and in writing), defend Landlord, Landlord's Agents, and Landlord's officers,
directors, shareholders, partners, employees, contractors, property managers, agents
and mortgagees and other lien holders, from and against any and all Losses (as defined
below), whenever such Losses arise, arising from or related to: (a) any violation
or alleged violation by Tenant or any of Tenant's Parties of any of the requirements,
ordinances, statutes, regulations or other laws referred to in this Paragraph 11.b,
including, without limitation, the
                          --------------                                     Environmental
Laws, whether such violation or alleged violation occurred prior to, on, or after
the Commencement Date; (b) any breach of the provisions of this Paragraph 11.b by
Tenant or any of Tenant's Parties; or (c) any Hazardous Use - --------------   
                                                            on, about or from the
Premises by Tenant or any of Tenant's Parties of any Hazardous Materials (whether
or not approved by Landlord under this Lease), whether such Hazardous Use occurred
prior to, on, or after the Commencement Date.  The term "Losses" shall mean all
claims, demands, expenses, actions,
                  ------                                                     judgments,
damages (whether consequential, direct or indirect, known or unknown, foreseen or
unforeseen), penalties, fines, liabilities, losses of every kind and nature (including,
without limitation, property damage, diminution in value of Landlord's interest
in the Premises, damages for the loss of restriction on use of any space or amenity
within the Premises, damages arising from any adverse impact on marketing space
in the Premises, sums paid in settlement of claims and any costs and expenses associated
with injury, illness or death to or of any person), suits, administrative proceedings,
costs and fees, including, but not limited to, attorneys' and consultants' fees
and expenses, and the costs of cleanup, remediation, removal and restoration, that
are in any way related to any matter covered by the foregoing indemnity.
 
                (ix)   Survival. The provisions of this Paragraph 11.b shall
                       --------                         -------------- survive the
expiration or earlier termination of this Lease.
 
           C.   Special Provisions Relating to The Americans With Disabilities
                -------------------------------------------------------------- Act
of 1990. - ----------- 
 
                (i)  Allocation of Responsibility to Landlord. As between
                     ---------------------------------------- Landlord and Tenant,
Landlord shall be responsible that the Common Area owned by Landlord complies with
the requirements of Title III of the Americans with Disabilities Act of 1990 (42
U.S.C. 12181, et seq., The Provisions Governing Public Accommodations and Services
Operated by Private Entities), and all regulations promulgated thereunder, and all
amendments, revisions or modifications thereto now or hereafter adopted or in effect
in connection therewith (hereinafter collectively referred to as the "ADA"), and
to take such actions and make such alterations and improvements as are necessary
for such compliance; provided, however, that to the extent such requirements arise
from the construction of any Alterations to the Premises made by or on behalf of
Tenant, then as between Landlord and Tenant, Tenant shall be responsible that the
Common Area complies with the requirements of the ADA, and to take such actions
and make such
 
                                       24 

 alterations and improvements as are necessary for such compliance.
 
                (ii)   Allocation of Responsibility to Tenant. Except as
                       --------------------------------------  expressly provided
in the Work Letter, as between Landlord and Tenant, Tenant, at its sole cost and
expense, shall be responsible that the Premises (and all modifications made by Tenant
of access to the Premises from the street), and all alterations and improvements
in the Premises (including without limitation the Tenant Improvements), and Tenant's
use and occupancy of the Premises, and Tenant's performance of its obligations under
this Lease, comply with the requirements of the ADA, and to take such actions and
make such alterations and improvements as are necessary for such compliance; provided,
however, that Tenant shall not make any such alterations or improvements except
upon Landlord's prior written consent (which shall not be unreasonably withheld)
pursuant to the terms and conditions of this Lease. If Tenant fails diligently to
take such actions or make such alterations or improvements as are necessary for
such compliance, Landlord may, but shall not be obligated to, take such actions
and make such alterations and improvements and may recover all of the costs and
expenses of such actions, alterations and improvements from Tenant as Additional
Rent. Tenant shall be entitled to utilize the Tenant Improvements Allowance to pay
for the cost of any improvements required by ADA that are triggered by the construction
of the Tenant Improvements.
 
                (iii)  General. Notwithstanding anything in this Lease contained
                       -------  to the contrary, no act or omission of either party,
including any approval, consent or acceptance by it or its agents, employees or
other representatives, shall be deemed an agreement, acknowledgment, warranty, or
other representation by it that the other party has complied with the ADA as provided
under Paragraphs 11.C.(i) or 11.c.(ii) or that any action, alteration or improvement
- -------------------    ---------                                             
 by it complies or will comply with the ADA as provided under Paragraphs 11.c.(i)
                                                              -------------------
or 11.c.(ii) or constitutes a waiver by it of the other party's obligations to
    ---------                                                                  
comply with the ADA under Paragraphs 11.c.(i) or 11.c.(ii) of this Lease or
                           -------------------    ---------                  otherwise.
 Any failure of either party to comply with its obligations of the ADA under Paragraphs
11.c.(i) or 11.c.(ii) shall not relieve such party from any
           -------------------    ---------                                    
  obligations under this Lease or in the case of Landlord's failure to comply under
Paragraph 11.c.(i), constitute or be construed as a constructive or other
       ------------------                                                      
 eviction of Tenant or disturbance of Tenant's use and possession of the Premises.
 
           D.   Use and Maintenance of Common Area.  Tenant and its employees and
                ----------------------------------                             
  invitees shall have the non-exclusive right to use the Common Area in common with
other persons during the Term of this Lease, subject to the CC&Rs and such reasonable
rules and regulations as may from time to time be deemed necessary or advisable
in Landlord's reasonable discretion for the proper and efficient operation and maintenance
of the Common Area.  Such rules and regulations may include, among other things,
the hours during which the Common Area shall be open for use.  Landlord shall maintain
and operate the Common Area from time to time owned by Landlord in good condition,
provided that any damage thereto, other than normal wear and tear, occasioned by
the act of Tenant or its employees or invitees shall be paid by Tenant upon demand
by Landlord.
 
      12.  Quiet Enjoyment.
           --------------- 
 
                                       25 
 
           Landlord covenants that Tenant, upon performing the terms, conditions
and covenants of this Lease, shall have quiet and peaceful possession of the Premises
as against any person claiming the same by, through or under Landlord.
 
      13.  Alterations.
           ----------- 
 
           A.   Alteration Rights.  After the Commencement Date, Tenant shall not
                -----------------                                              
  make or permit any Alterations in, on or about the Premises, except for nonstructural
Alterations (which shall not include any modifications to the mechanical or electrical
systems of the Building, nor any penetration of the Building's roof) not exceeding
Ten Thousand Dollars ($10,000.00) in aggregate cost during any period of twelve
(12) consecutive months, without the prior written consent of Landlord, and according
to plans and specifications approved in writing by Landlord, which consent shall
not be unreasonably withheld. Notwithstanding the foregoing Tenant shall not, without
the prior written consent of Landlord, make any:
 
                (i)    Alterations to the exterior of the Building;
 
                (ii)   Alterations to the roof of the Building; and
 
                (iii)  Alterations visible from outside the Building, to which Landlord
may withhold Landlord's consent on wholly aesthetic grounds.
 
           B.   Performance of Alterations.  All Alterations shall be installed
                --------------------------                                     
at Tenant's sole expense, in compliance with all applicable laws, by a licensed
contractor, shall be done in a good and workmanlike manner conforming in quality
and design with the Premises existing as of the Commencement Date, and shall not
diminish the value of either the Building or the Premises.  All Alterations made
by Tenant shall be and become the property of Landlord upon installation and shall
not be deemed Tenant's Personal Property, and Tenant shall not remove any Alterations
from the Premises unless Tenant has first obtained Landlord's written consent to
such removal.  Landlord may require Tenant to remove, at Tenant's expense, any Alterations
from the Premises at the expiration or earlier termination of this Lease; provided,
however, that at the time any Alterations are constructed, Tenant shall have the
right to request Landlord's written approval (which shall not be unreasonably withheld
or delayed) that Landlord will not require the removal of such Alterations at the
expiration or earlier termination of this Lease.  Notwithstanding Alterations made
by it to the Premises.  Tenant shall give Landlord written notice of Tenant's intention
to perform work on the Premises at least ten (10) days prior to the commencement
of such work to enable Landlord to post and record a Notice of Nonresponsibility
or other notice deemed proper before the commencement of any such work.
 
           C.   Trade Fixtures.  Landlord acknowledges that Tenant may lease from
                --------------                                                 
  or finance with a third party (collectively, a "Trade Fixture Lessor") all or
a
                                                 --------------------          
 portion of Tenant's Personal Property. Landlord shall duly execute and properly
deliver any waivers or consents which may reasonably be required by any proposed
Trade Fixture Lessor in connection with the leasing or financing of such Tenant's
Personal Property, so long as such waivers and consents shall include the following:
(i) the Trade Fixture Lessor shall agree to repair any damage to the 
 
                                       26 

 Premises caused by the Trade Fixtures Lessor's removal of Tenant's Personal Property
from the Premises, and (ii) Landlord's waiver and consent shall be of no force or
effect after the thirtieth (30th) day following the end of the Term or earlier termination
of this Lease.
 
      14.  Surrender of the Premises.
           ------------------------- 
 
           Upon the expiration or earlier termination of the Term, Tenant shall
surrender the Premises to Landlord in its condition existing as of the date of substantial
completion of the Improvements, normal wear and tear and fire or other casualty
excepted, with all interior walls repaired if damaged, all broken, marred or nonconforming
acoustical ceiling tiles replaced, all windows washed, the plumbing and electrical
systems and lighting in good order and repair, including replacement of any burned
out or broken light bulbs or ballasts, the HVAC equipment serviced and repaired
by a reputable and licensed service firm, and all floors cleaned, all to the reasonable
satisfaction of Landlord.  Tenant shall remove from the Premises all of Tenant's
Alterations required to be removed pursuant to Paragraph 13, and all Tenant's Personal
                                    ------------                            Property,
and repair any damage and perform any restoration work caused by such removal. 
If Tenant fails to remove such Alterations and Tenant's Personal Property, and such
failure continues after the expiration or earlier termination of this Lease, Landlord
may retain such Alterations and Tenant's Property and all rights of Tenant with
respect to it shall cease, or Landlord may place all or any portion of such Alterations
and Tenant's Property in public storage for Tenant's account. Tenant shall be liable
to Landlord for costs of removal of any such Alterations and Tenant's Personal Property
and storage and transportation costs of same, and the cost of repairing and restoring
the Premises, together with interest at the Interest Rate from the date of expenditure
by Landlord.  If the Premises are not so surrendered at the expiration or earlier
termination of this Lease, Tenant shall indemnify Landlord and Landlord's Agents
against all loss or liability, including reasonable attorneys' fees and costs, resulting
from delay by Tenant in so surrendering the Premises.
 
           Normal wear and tear, for the purposes of this Lease, shall be construed
to mean wear and tear caused to the Premises by a natural aging process which occurs
in spite of prudent application of the best standards for maintenance, repair and
janitorial practices.  It is not intended, nor shall it be construed, to include
items of neglected or deferred maintenance which would have or should have been
attended to during the Term of the Lease if the best standards had been applied
to properly maintain and keep the Premises at all times in good condition and repair.
 
      15.  Impositions and Real Property Taxes.
           ----------------------------------- 
 
           A.   Payment by Tenant.  Tenant shall pay all Impositions prior to
                -----------------                                             delinquency.
 If billed directly, Tenant shall pay such Impositions and concurrently present
to Landlord satisfactory evidence of such payments.  If any Impositions are billed
to Landlord or included in bills to Landlord for Real Property Taxes, then Tenant
shall pay to Landlord all such amounts within fifteen (15) days after receipt of
Landlord's invoice therefor.  If applicable law prohibits Tenant from reimbursing
Landlord for an Imposition, but Landlord may lawfully increase the Monthly Rent
to account for Landlord's payment of such Imposition, the Monthly Rent payable to
Landlord shall be increased so that the amount of such increased Monthly Rent, together
with
 
                                       27 

 any accompanying increases in the Real Property Taxes payable by Tenant with respect
to such Imposition, are sufficient to net to Landlord the same return without reimbursement
of such Imposition as would have been received by Landlord with reimbursement of
such Imposition. In addition, on or before April 10 and December 10 of each year
of the Term, Tenant shall pay directly to the San Mateo County assessor the Real
Property Taxes for the Premises as set forth on the assessors tax bill for the Premises.
If, however, the Premises are not a separate parcel for tax purposes but constitute
a portion of a larger tax parcel or parcels, the Real Property Taxes payable by
Tenant under this Lease shall be a percentage of the Real Property Taxes payable
for such parcel or parcels, which percentage shall be determined by dividing the
Rentable Area of the Building by the total Rentable Area of all buildings on such
parcel or parcels and multiplying the result by 100, which Real Property Taxes shall
be payable by Tenant to Landlord monthly as part of the Common Area Maintenance
Costs.
 
                (i)    Tax Parcels. If Landlord determines in its reasonable
                       ----------- discretion that the configuration of tax parcels
within the Project (including without limitation the tax parcel on which the Premises
is situated) causes the allocation of Real Property Taxes between the affected tax
parcels to be unfair or inequitable, Landlord reserves the right to internally reallocate
the Real Property Taxes assessed against such affected tax parcels in a manner that
reasonably addresses such unfairness or inequity. If Landlord effects any such reallocation,
then the Real Property Taxes payable by Tenant under this Lease shall be those Real
Property Taxes allocated to the Premises pursuant to this Paragraph 15.A.(i). -
------------------ 
 
                (ii)   Payment. Promptly following payment of the Real Property
                       ------- Taxes, Tenant shall provide Landlord with copies
of paid receipts or other documentary evidence that the Real Property Taxes have
been paid by Tenant. If Tenant fails to pay the Real Property Taxes on or before
April 10 and December 10, respectively, or if Tenant fails to pay its share of Real
Property Taxes as part of the Common Area Maintenance Costs, Tenant shall pay to
Landlord any penalty incurred by such late payment. In addition, Tenant shall pay
any Real Property Tax not included within the county tax assessor's tax bill within
ten (10) days after being billed for same by Landlord. The foregoing dates are based
on the dates established by the county as the dates on which Real Property Taxes
become delinquent if not paid. If such delinquency dates change, the dates on which
Tenant must pay the Real Property Taxes for the Premises shall be at least ten (10)
days prior to the new delinquency dates. Assessments, taxes, fees, levies and charges
may be imposed by governmental agencies for such purposes as fire protection, street,
sidewalk, road, utility construction and maintenance, refuse removal and for other
governmental services which may formerly have been provided without charge to property
owners or occupants. It is the intention of the parties that all new and increased
assessments, taxes, fees, levies and charges are to be included within the definition
of Real Property Taxes for the purposes of this Lease.
 
           B.   Taxes on Tenant Improvements and Personal Property.  Tenant shall
                --------------------------------------------------             
  pay any increase in Real Property Taxes resulting from any and all Alterations
and Tenant Improvements of any kind whatsoever placed in, on or about the Premises
for the benefit of, at the request of, or by Tenant.  Tenant shall pay prior to
delinquency all taxes assessed or levied against Tenant's Personal Property in,
on or about the Premises or elsewhere.  When possible, 
 
                                       28 

 Tenant shall cause its Personal Property to be assessed and billed separately from
the Premises and the real property or Personal Property of Landlord.
 
           C.   Proration.  Tenant's liability to pay Real Property Taxes shall
                ---------                                                      
be prorated on the basis of a 360-day year to account for any fractional portion
of a fiscal tax year included at the commencement or expiration of the Term. With
respect to any assessments which may be levied against or upon the Premises on all
or any portion of the Project, or which under the laws then in force may be evidenced
by improvements or other bonds or may be paid in annual installments, only the amount
of such annual installment (with appropriate proration for any partial year) and
interest due thereon shall be included within the computation of the annual Real
Property Taxes levied against the Premises or such portion of the Project, as applicable.
 
      16.  Utilities and Services.
           ---------------------- 
 
           Tenant shall be responsible for and shall pay promptly all charges for
water, gas, electricity, telephone, refuse pick-up, janitorial service and all other
utilities, materials and services furnished directly to or used by Tenant in, on
or about the Premises during the Term, together with any taxes thereon. If any utility,
material or service is not separately charged or metered to any portion of the Premises,
Tenant shall pay to Landlord, within ten (10) days after written demand therefor,
Tenant's pro rata share of the total cost thereof as may be determined by Landlord.
Landlord shall not be liable in damages or otherwise for any failure or interruption
of any utility service or other service furnished to the Premises, except that resulting
from the gross negligence or willful misconduct of Landlord. Tenant shall have the
right to contract directly with vendors for janitorial and maintenance services,
provided such vendors must be approved in advance by Landlord, which approval shall
not be unreasonably withheld; and provided further, that Tenant shall have no right
to contract with any vendor to maintain the Building's HVAC system, which shall
be the sole responsibility of Landlord as set forth in Paragraph 17.A.
                                                        -------------- 
 
      17.  Repair and Maintenance.
           ---------------------- 
 
           A.   Landlord's Obligations.  Landlord shall keep in good order,
                ----------------------                                      condition
and repair the structural parts of the Building, which structural parts consist
only of the foundation, subflooring, exterior walls (excluding the interior of all
walls and the exterior and interior of all windows, doors, ceilings, and plate glass),
and roof of the Building, and all plumbing and electrical facilities leading up
to (but not situated within) the Building, except for any damage thereto caused
by the negligence or willful acts or omissions of Tenant or of Tenant's agents,
employees or invitees, or by reason of the failure of Tenant to perform or comply
with any terms of this Lease, or caused by Alterations made by Tenant or by Tenant's
agents, employees or contractors.  It is an express condition precedent to all obligations
of Landlord to repair and maintain that Tenant shall have notified Landlord of the
need for such repairs or maintenance.  Tenant waives the provisions of Sections
1941 and 1942 of the California Civil Code and any similar or successor law regarding
Tenant's right to make repairs and deduct the expenses of such repairs from the
Rent due under this Lease. Landlord shall keep in good order, condition, repair
and maintenance the Building's HVAC system and roof, and shall maintain an HVAC
system preventive maintenance service contract from a qualified vendor for the purpose
of maintaining 
 
                                       29 

 the Building's HVAC system, and a roof maintenance service contract from a qualified
vendor for the purpose of maintaining the Building's roof. Landlord shall determine
in its sole discretion whether any such vendor is qualified. Any and all costs of
any maintenance or repair of the HVAC system or the roof (including without limitation
the cost of maintaining HVAC system preventative maintenance contracts and roof
maintenance service contracts) shall be included in the Common Area Maintenance
Costs payable solely by Tenant for the year in which such cost is incurred. Landlord
may elect, in its sole discretion, to paint the exterior of the Building and/or
to replace or perform capital improvements to any area or aspect of the Building
which Landlord is required keep in good order, condition and repair. If Landlord
decides, in its sole discretion, to replace the roof of the Building during the
Term, then the cost of so replacing the roof, together with interest at the Interest
Rate, shall be amortized on a straight-line basis over the useful life of the roof
(as determined by Landlord in its sole discretion) (the "Useful Life"), and the
                                                      ----------- entire amount
of such amortized costs and interest shall be included in the monthly Common Area
Maintenance Costs payable solely by Tenant during the entire period over which such
costs are amortized, until Tenant has paid to Landlord that proportion of the total
amount of such amortized costs equal to (a) the number of months remaining during
the Term as of the date such roof replacement was completed, divided by (b) the
number of months of the Useful Life; provided that in no event shall such proportion
exceed one hundred percent (100%). For the purposes of example only and not by way
of limitation, if the Building's roof is replaced twenty-four (24) months before
the end of the Term, at a cost of Fifty Thousand Dollars ($50,000.00), and the Useful
Life is one hundred twenty (120) months, then (a) the cost of such replacement shall
be amortized at the rate of Four Hundred Sixteen and 67/100ths Dollars ($416.67)
per month, with interest at the Interest Rate, and (b) the amount to be included
in the monthly Common Area Maintenance Costs payable solely by Tenant for the balance
of the Term shall equal Four Hundred Sixteen and 67/100ths Dollars ($416.67), with
interest at the Interest Rate, until Tenant has paid to Landlord a total aggregate
amount of Ten Thousand Dollars ($10,000.00), together with interest at the Interest
Rate, towards such amortized costs (i.e., Fifty Thousand Dollars ($50,000.00) multiplied
by [Twenty-Four (24) months divided by One Hundred Twenty (120) months]). If Tenant
exercises an Option to Extend, the total length of the Term (i.e., the initial Term
and each Extended Term) shall be utilized to calculate the maximum amount of such
amortized costs that shall be includable in the monthly Common Area Maintenance
Costs payable solely by Tenant pursuant to this Paragraph 17.A.
      -------------- 
 
           It is the express intent of the parties that except as specifically set
forth in this Paragraph 17.A, Landlord shall have no obligation whatsoever
                   --------------                                              
to repair or maintain the Building, and that Tenant shall be responsible for performing
all repair, operation, and maintenance of the Building except for those tasks specifically
described in this Paragraph 17.A.
                                            -------------- 
 
           B.   Tenant's Obligations.  Tenant shall at all times and at its sole
                --------------------                                           
 cost and expense clean, keep and maintain in good order, condition and repair (and
replace, if necessary) every part of the Premises which is not within Landlord's
obligation pursuant to Paragraph 17.A.  Tenant's repair and
                                   --------------                       maintenance
obligations shall include without limitation all plumbing and electrical facilities
situated within the Building, fixtures, interior walls and ceiling, floors, windows,
window frames, doors, entrances, plate glass, showcases, skylights, all lighting
fixtures, lamps, fans and any exhaust equipment and systems, all mechanical systems
(but not the 
 
                                       30 

 HVAC system), any automatic fire extinguisher equipment within the Building, all
security systems and alarms, all electrical motors and all other appliances and
equipment of every kind and nature located in, upon or about the Building or the
Premises. Tenant shall also be responsible for all pest control within the Premises.
 
           C.   Conditions Applicable to Repairs.  All repairs, replacements and
                --------------------------------                               
 reconstruction made by or on behalf of Tenant or any person claiming through or
under Tenant shall be made and performed (i) at Tenant's sole cost and expense,
in a good and workmanlike manner and at such time and in such manner as Landlord
may reasonably designate, (ii) by contractors approved in advance by Landlord, (iii)
so that the repairs, replacements or reconstruction shall be at least equal in quality,
value and utility to the original work or installation, (iv) in accordance with
such reasonable requirements as Landlord may impose with respect to insurance and
bonds to be obtained by Tenant in connection with the proposed work, and (v) in
accordance with any rules and regulations for the Building as may be adopted by
Landlord from time to time and in accordance with all applicable laws and regulations
of governmental authorities having jurisdiction over the Premises.
 
           D.   Landlord's Rights.  If Tenant fails to perform Tenant's
                -----------------                                       obligations
under Paragraph 17.B, Landlord may in its sole discretion give
                   --------------                                           Tenant
notice of such work as is reasonably required to fulfill such obligations. If Tenant
fails to commence the work within thirty (30) days after receipt of such notice
and diligently prosecute the work to completion, then Landlord shall have the right
(but not the obligation) to do such acts or expend such funds at the expense of
Tenant as are reasonably required to perform such work.  Any amount so expended
by Landlord shall be paid by Tenant to Landlord promptly after demand with interest
at the Interest Rate.  Landlord shall have no liability to Tenant for any damage
to, or interference with Tenant's use of, the Premises, or inconvenience to Tenant
as a result of performing any such work.
 
           E.   Compliance with Governmental Regulations.  Tenant shall, at its
                ----------------------------------------                       
sole cost and expense, comply with, including the making by Tenant of any Alteration
to the Premises, all present and future regulations, rules, laws, ordinances, and
requirements of all governmental authorities (including, without limitation state,
municipal, county and federal governments and their departments, bureaus, boards
and officials) applicable to the Premises or the Building.
 
      18.  Liens.
           ----- 
 
           Tenant shall keep the Building and the Premises free from any liens arising
out of any work performed, materials furnished or obligations incurred by or on
behalf of Tenant and hereby agrees to indemnify, defend, protect and hold Landlord
and Landlord's Agents harmless from and against any and all loss, claim, damage,
liability, cost and expense, including attorneys' fees and costs, in connection
with or arising out of any such lien or claim of lien. Tenant shall cause any such
lien imposed to be released of record by payment or posting of a proper bond acceptable
to Landlord within ten (10) days after written request by Landlord. Tenant shall
give Landlord written notice of Tenant's intention to perform work on the Premises
which might result in any claim of lien at least ten (10) days prior to the commencement
of such work to 
 
                                       31 

 enable Landlord to post and record a Notice of Nonresponsibility or any such other
notice(s) as Landlord may deem appropriate. If Tenant fails to so remove any such
lien within the prescribed ten 10-day period, then Landlord may do so at Tenant's
expense and Tenant shall reimburse Landlord for such amounts upon demand. Such reimbursement
shall include all costs incurred by Landlord including Landlord's reasonable attorneys'
fees with interest thereon at the Interest Rate.
 
      19.  Landlord's Right to Enter the Premises.
           -------------------------------------- 
 
           Tenant shall permit Landlord and Landlord's Agents to enter the Premises
at all reasonable times with reasonable notice, except for emergencies in which
case no notice shall be required, to inspect the same, to post Notices of Nonresponsibility
and similar notices, and real estate "For Sale" signs, to show the Premises to interested
parties such as prospective lenders and purchasers, to make necessary repairs, to
discharge Landlord's obligations under this Lease, to discharge Tenant's obligations
under this Lease when Tenant has failed to do so within a reasonable time after
written notice from Landlord, and at any reasonable time within one hundred and
eighty (180) days prior to the expiration of the Term, to place upon the Building
ordinary "For Lease" signs and to show the Premises to prospective tenants.
 
      20.  Signs.
           ----- 
 
           Subject to Tenant obtaining all necessary approvals from the City of
Redwood City and subject to Landlord's review and approval of plans and specifications
for any proposed signage, which approval may be withheld only in Landlord's commercially
reasonable judgment, Tenant shall have the exclusive right to install identification
signage on the exterior of the Building, so long as such signage complies with Landlord's
project sign program. Tenant shall have no right to maintain any Tenant identification
sign in any other location in, on or about the Building or the Premises and shall
not display or erect any other Tenant identification sign, display or other advertising
material that is visible from the exterior of the Building. Any changes to the size,
design, color or other physical aspects of Tenant's identification sign(s) shall
be subject to the Landlord's prior written approval, which shall not be unreasonably
withheld, and any appropriate municipal or other governmental approvals.  The cost
of Tenant's sign(s) and their installation, maintenance and removal shall be Tenant's
sole cost and expense. If Tenant fails to maintain its sign(s), or, if Tenant fails
to remove its sign(s) upon termination of this Lease, Landlord may do so at Tenant's
expense and the amounts expended by Landlord in doing so shall be immediately payable
by Tenant to Landlord as Additional Rent.
 
      21.  Insurance.
           --------- 
 
           A.   Indemnification.  Tenant shall indemnify, defend, protect and
                ---------------                                               hold
Landlord harmless of and from any and all loss, liens, liability, claims, causes
of action, damage, injury, cost or expense arising out of or in connection with,
or related to (i) the making of Alterations, or (ii) injury to or death of persons
or damage to property occurring or resulting directly or indirectly from: (A) the
use or occupancy of, or the conduct of business in, the Premises; (B) the use, storage,
release or disposal by Tenant or Tenant's employees, agents, 
 
                                       32 

 contractors, licensees or invitees, of any Hazardous Materials in or about the
Premises or any other portion of the Project; (C) any other occurrence or condition
in or on the Premises; and (D) acts, neglect or omissions of Tenant, its officers,
directors, agents, employees, invitees or licensees in or about any portion of the
Project. Tenant's indemnity obligation includes reasonable attorneys' fees and costs,
investigation costs and all other reasonable costs and expenses incurred by Landlord.
If Landlord disapproves the legal counsel proposed by Tenant for the defense of
any claim indemnified against hereunder, Landlord shall have the right to appoint
its own legal counsel, the reasonable fees, costs and expenses of which shall be
included as part of Tenant's indemnity obligation hereunder. The indemnification
contained in this Section
                                                                       ------- 21.A
shall extend to the officers, directors, shareholders, partners, employees, - ----
agents and representatives of Landlord. The obligations assumed by Tenant herein
shall survive this Lease. Notwithstanding the foregoing, Landlord shall have the
right, in its sole discretion, but without being required to do so, to defend, adjust,
settle or compromise any claim, obligation, debt, demand, suit or judgment against
Landlord arising out of or in connection with the matters covered by the foregoing
indemnity and, in such event, Tenant shall reimburse Landlord for all reasonable
charges and expenses incurred by Landlord in connection therewith, including reasonable
attorneys' fees; provided, however, that Landlord shall not undertake any unilateral
action or settlement so long as Tenant or an insurance company, at its or their
sole expense, is contesting in good faith, diligently and with continuity such claim,
action, obligation, demand or suit, and so long as such claim, action, obligation,
demand or suit does not have or threaten to have a material adverse impact on Landlord's
assets, reputation or business affairs.
 
           B.   Tenant's Insurance.  Tenant agrees to maintain in full force and
                ------------------                                             
 effect at all times during the Term, at its sole cost and expense, for the protection
of Tenant and Landlord, as their interests may appear, policies of insurance issued
by a responsible carrier or carriers acceptable to Landlord which afford the following
coverages:
 
                (i)    Commercial general liability insurance in an amount not less
than Three Million and no/100ths Dollars ($3,000,000.00) combined single limit for
both bodily injury and property damage which includes blanket contractual liability
broad form property damage, personal injury, completed operations, and products
liability, which policy shall name Landlord and Landlord's Agents as additional
insureds and shall contain a provision that "the insurance provided Landlord hereunder
shall be primary and non-contributing with any other insurance available to Landlord
with respect to any damage, loss, liability or expense covered by Tenant's indemnity
obligations under Paragraph
                                                                      ---------
21.A of the Lease." - ----
 
                (ii)   Causes of loss-special form property insurance (including,
without limitation, vandalism, malicious mischief, inflation endorsement, and sprinkler
leakage endorsement) on Tenant's Personal Property located on or in the Premises.
Such insurance shall be in the full amount of the replacement cost, as the same
may from time to time increase as a result of inflation or otherwise. As long as
this Lease is in effect, the proceeds of such policy shall be used for the repair
and replacement of such items so insured.  Landlord shall have no interest in the
insurance proceeds on Tenant's Personal Property. Notwithstanding the foregoing,
Tenant shall have the right, at its election, to self-insure with respect to any
loss or damage to Tenant's Personal Property.
 
                                       33 
 
                (iii)  Boiler and machinery insurance, including steam pipes, pressure
pipes, condensation return pipes and other pressure vessels and HVAC equipment,
including miscellaneous electrical apparatus, in an amount satisfactory to Landlord.
 
                (iv)   Workers compensation insurance in the manner and to the extent
required by applicable law and with limits of liability not less than the minimum
required under applicable law, covering all employees of Tenant having any duties
or responsibilities in or about the Premises.
 
           C.   Premises Insurance.  During the Term Landlord shall maintain
                ------------------                                           causes
of loss-special form property insurance (including inflation endorsement, sprinkler
leakage endorsement, and, at Landlord's option, earthquake and flood coverage) on
the Building, excluding coverage of all Tenant's Personal Property located on or
in the Premises, but including the Tenant Improvements.  Such insurance shall also
include insurance against loss of rents, including, at Landlord's option, coverage
for earthquake and flood, in an amount equal to the Monthly Rent and Additional
Rent, and any other sums payable under the Lease, for a period of at least twelve
(12) months commencing on the date of loss. Such insurance shall name Landlord and
Landlord's Agents as named insureds and include a lender's loss payable endorsement
in favor of Landlord's lender (Form 438 BFU Endorsement).  Tenant shall reimburse
Landlord monthly, as Additional Rent, for one-twelfth (12th) of the annual cost
of such insurance on the first day of each calendar month of the Term, prorated
for any partial month, or on such other periodic basis as Landlord shall elect.
If the insurance premiums are increased after the Commencement Date for any reason,
including without limitation due to an increase in the value of the Building or
its replacement cost, or due to Tenant's use of the Premises or any improvements
installed by Tenant, Tenant shall pay such increase within ten (10) days of notice
of such increase.  Landlord may, in its sole discretion, maintain the insurance
coverage described in this Paragraph 21.C as part of an umbrella insurance policy
                   --------------                                         covering
other properties owned by Landlord.  Notwithstanding the foregoing, so long as the
original Landlord under this Lease continues to be the Landlord under this Lease,
and subject to the following conditions, Tenant may elect to carry the insurance
required by this Paragraph 21.C if Tenant is able to obtain
                                      --------------                           
 the coverage required hereunder at a cost less than that charged by Landlord's
insurer. Tenant's right to carry such insurance shall be subject to the following
conditions: (i) all Holders, defined below, shall have approved Tenant's right to
carry such insurance, (ii) such insurance shall name Landlord, and all parties designated
by Landlord, as additional insureds, and (iii) such insurance shall provide Landlord
with at least the same coverage and rights as Landlord would be entitled to receive
if Landlord had obtained such insurance.
 
           D.   Increased Coverage.  Upon demand, Tenant shall provide Landlord,
                ------------------                                             
 at Tenant's expense, with such increased amount of existing insurance, and such
other insurance as Landlord or Landlord's lender may reasonably require to afford
Landlord and Landlord's lender adequate protection.
 
           E.   Failure to Maintain.  If Tenant fails to maintain any insurance
                -------------------                                            
coverage that Tenant is required to maintain under this Paragraph 21, and
                                                         ------------      Landlord
incurs any liability to its insurance carrier arising out of Tenant's failure to
so maintain such insurance coverage, then 
 
                                       34 

 any and all loss or damage Landlord shall sustain by reason thereof, including
attorneys' fees and costs, shall be borne by Tenant and shall be immediately paid
by Tenant upon its receipt of a bill therefor and evidence of such loss. Nothing
contained in this Paragraph 21.E shall be deemed to limit or affect any
                           -------------- other remedies or rights available to
Landlord under this Lease that arise from Tenant's failure to so maintain such insurance
coverage.
 
           F.   Insurance Requirements.  All insurance shall be in a form
                ----------------------                                    satisfactory
to Landlord and shall be carried in companies that have a general policy holder's
rating of not less than "A" and a financial rating of not less than Class "X" in
the most current edition of Best's Insurance Reports; and
                                               ------------------------      shall
provide that such policies shall not be subject to material alteration or cancellation
except after at least thirty (30) days' prior written notice to Landlord. The policy
or policies, or duly executed certificates for them, together with satisfactory
evidence of payment of the premiums thereon shall be deposited with Landlord prior
to the Commencement Date, and upon renewal of such policies, not less than thirty
(30) days prior to the expiration of the term of such coverage.  If Tenant fails
to procure and maintain the insurance it is required to maintain under this Paragraph
21, Landlord may, but shall not be
                                 ------------                                 required
to, order such insurance at Tenant's expense and Tenant shall reimburse Landlord
therefor.  Such reimbursement shall include all costs incurred by Landlord in obtaining
such insurance including Landlord's reasonable attorneys' fees, with interest thereon
at the Interest Rate.
 
           G.   Waiver and Release.  Except to the extent due to the negligence
                ------------------                                             
or willful misconduct of Landlord, Landlord shall not be liable to Tenant or Tenant's
employees, agents, contractors, licenses or invitees for, and Tenant waives as against
and releases Landlord and Landlord's Agents from, all claims for loss or damage
to any property or injury, illness or death of any person in, upon or about the
Premises and/or any other portion of the Project, arising at any time and from any
cause whatsoever (including without limitation any claim caused in whole or in part
by the act, omission, or neglect of other tenants, contractors, licensees, invitees
or other occupants of the Project or their agents or employees; and any claim arising
from any construction activities taking place in, upon or about the Premises and/or
any other portion of the Project).  Landlord and Landlord's Agents shall not be
liable for any latent defect in the Premises.
 
      22.  Waiver of Subrogation.
           --------------------- 
 
           Landlord and Tenant each hereby waive all rights of recovery against
the other on account of loss or damage occasioned by such waiving party to its property
or the property of others under its control, to the extent that such loss or damage
would be covered by any causes of loss-special form policy of insurance or its equivalent
required to be or actually carried under Paragraph
                                                                      ---------
21.  Tenant and Landlord shall, upon obtaining policies of insurance required -
--                                                                            hereunder,
give notice to the insurance carrier that the foregoing mutual waiver of subrogation
is contained in this Lease and Tenant and Landlord shall cause each insurance policy
obtained by such party to provide that the insurance company waives all right of
recovery by way of subrogation against either Landlord or Tenant in connection with
any damage covered by such policy.
 
                                       35 
 
      23.  Damage or Destruction.
           --------------------- 
 
           A.   Landlord's Obligation to Rebuild.  If all or any part of the
                --------------------------------                             Building
is damaged or destroyed, Landlord shall promptly and diligently repair the same
unless it has the right to terminate this Lease as provided herein and it elects
to so terminate.
 
           B.   Right to Terminate.  Landlord shall have the right to terminate
                ------------------                                             
this Lease in the event any of the following events occur:
 
                (i)  insurance proceeds from the insurance Landlord is required
to carry pursuant to Paragraph 21.C, or that Landlord actually carries, are not
available to pay one hundred percent (100%) of the cost of such repair, excluding
the deductible for which Tenant shall be responsible; provided, however, that if
Tenant pays to Landlord, in immediately available funds, within thirty (30) days
after such casualty, any shortfall in such insurance proceeds, as reasonably determined
by Landlord, then Landlord shall have no right to terminate the Lease pursuant to
this item (i);
 
                (ii)  the Building cannot, with reasonable diligence, be fully repaired
by Landlord within three hundred sixty (360) days after the date of the damage or
destruction; or
 
                (iii) the Building cannot be safely repaired because of the presence
of hazardous factors, including, but not limited to, earthquake faults, radiation,
Hazardous Materials and other similar dangers.
 
           If Landlord elects to terminate this Lease, Landlord may give Tenant
written notice of its election to terminate within thirty (30) days after such damage
or destruction, and this Lease shall terminate fifteen (15) days after the date
Tenant receives such notice and both Landlord and Tenant shall be released of all
further liability under this Lease (except to the extent any provision of this Lease
expressly survives termination and except that Landlord shall return to Tenant the
Security Deposit).  If Landlord elects not to terminate the Lease, subject to Tenant's
termination right set forth below, Landlord shall promptly commence the process
of obtaining necessary permits and approvals and repair of the Building as soon
as practicable, and this Lease will continue in full force and affect.  All insurance
proceeds from insurance under Paragraph 21, excluding proceeds for Tenant's Personal
Property, shall be - ------------                                              
               disbursed and paid to Landlord.  Tenant shall be required to pay
to Landlord the amount of any deductibles payable in connection with any insured
casualties, unless the casualty was caused by the sole negligence or willful misconduct
of Landlord.
 
           Tenant shall have the right to terminate this Lease if the Building cannot,
with reasonable diligence, be fully repaired within three hundred sixty (360) days
from the date of damage or destruction. The determination of the estimated repair
periods in this Paragraph 23 shall be made by an independent,
                                  ------------                                 
licensed contractor or engineer within thirty (30) days after such damage or destruction.
 Landlord shall deliver written notice of the repair period to Tenant after such
determination has been made and Tenant shall exercise its right to terminate this
Lease, if at all, within ten (10) days of receipt of such notice from Landlord.
 Upon such 
 
                                       36 

 termination both Landlord and Tenant shall be released of all further liability
under this Lease (except to the extent any provision of this Lease expressly survives
termination).
 
           C.   Limited Obligation to Repair.  Landlord's obligation, should it
                ----------------------------                                   
elect or be obligated to repair or rebuild, shall be limited to the basic Building
and the Tenant Improvements and shall not include any Alterations made by Tenant.
 
           D.   Abatement of Rent.  Rent shall be temporarily abated
                -----------------                                    proportionately,
during any period when, by reason of such damage or destruction there is substantial
interference with Tenant's use of the Premises, having regard to the extent to which
Tenant may be required to discontinue Tenant's use of the Premises. Such abatement
of Rent shall be proportional to the extent of such interference with Tenant's use
of the Premises reasonably attributable to such damage or destruction (with the
extent of such interference to be reasonably determined by Landlord), and shall
commence upon such damage or destruction and end upon substantial completion by
Landlord of the repair or reconstruction which Landlord is obligated or undertakes
to perform. Tenant shall not be entitled to any compensation or damages from Landlord
for loss of the use of the Premises, damage to Tenant's Personal Property or any
inconvenience occasioned by such damage, repair or restoration. Tenant hereby waives
the provisions of Section 1932, Subdivision 2, and Section 1933, Subdivision 4,
of the California Civil Code, and the provisions of any similar law hereinafter
enacted.
 
           E.   Damage Near End of Term.  Anything herein to the contrary
                -----------------------                                   notwithstanding,
if the Building is destroyed or materially damaged during the last twelve (12) months
of the Term (unless Tenant has properly exercised an Option to Extend), then either
Landlord or Tenant may, at its option, cancel and terminate this Lease as of the
date of the occurrence of such damage, by delivery of written notice to the other
party and, in such event, upon such termination both Landlord and Tenant shall be
released of all further liability under this Lease (except to the extent any provision
of this Lease expressly survives termination).  If neither Landlord nor Tenant elects
to terminate this Lease, the repair of such damage shall be governed by Paragraphs
23.A and 23.B.
 
      24.  Condemnation.
           ------------ 
 
           If title to all of the Premises is taken for any public or quasi- public
use under any statute or by right of eminent domain, or so much thereof is so taken
so that reconstruction of the Premises will not, in Landlord's sole discretion,
result in the Premises being reasonably suitable for Tenant's continued occupancy
for the uses and purposes permitted by this Lease, this Lease shall terminate as
of the date that possession of the Premises or part thereof is taken, and upon such
termination both Landlord and Tenant shall be released of all further liability
under this Lease (except to the extent any provision of this Lease expressly survives
termination).  A sale by Landlord to any authority having the power of eminent domain,
either under threat of condemnation or while condemnation proceedings are pending,
shall be deemed a taking under the power of eminent domain for all purposes of this
Paragraph 24.
 
           If any part of the Premises is taken and the remaining part is reasonably
suitable 
 
                                       37 

 for Tenant's continued occupancy for the purposes and uses permitted by this Lease,
this Lease shall, as to the part so taken, terminate as of the date that possession
of such part of the Premises is taken, and upon such termination both Landlord and
Tenant shall be released of all further liability under this Lease with respect
to that portion of the Premises that is taken (except to the extent any provision
of this Lease expressly survives termination and except that Landlord shall return
to Tenant the Security Deposit). The Rent and other sums payable hereunder shall
be reduced in the same proportion that Tenant's use and occupancy of the Premises
is reduced. If any portion of the Common Area is taken, Tenant's Rent shall be reduced
only if such taking materially interferes with Tenant's use of the Common Area and
then only to the extent that the fair market rental value of the Premises is diminished
by such partial taking. If the parties disagree as to the amount of Rent reduction,
the matter shall be resolved by arbitration and such arbitration shall comply with
and be governed by the California Arbitration Act, Sections 1280 through 1294.2
of the California Code of Civil Procedure. Each party hereby waives the provisions
of Section 1265.130 of the California Code of Civil Procedure allowing either party
to petition the Superior Court to terminate this Lease in the event of a partial
taking of the Premises.
 
           All compensation or damages awarded or paid for any taking hereunder
shall belong to and be the property of Landlord, whether such compensation or damages
are awarded or paid as compensation for diminution in value of the leasehold, the
fee or otherwise, except that Tenant shall be entitled to any award allowed to Tenant
for the taking of Tenant's Personal Property, for the interruption of Tenant's business,
for its moving costs, or for the loss of its good will.  Except for the foregoing
allocation, no award for any partial or entire taking of the Premises shall be apportioned
between Landlord and Tenant, and Tenant assigns to Landlord its interest in the
balance of any award which may be made for the taking or condemnation of the Premises,
together with any and all rights of Tenant arising in or to the same or any part
thereof.
 
      25.  Assignment and Subletting.
           ------------------------- 
 
           A.   Landlord's Consent.  Subject to the provisions of Paragraph 25.G
                ------------------                                --------------
below, Tenant shall not enter into a Sublet without Landlord's prior written consent,
which consent shall not be unreasonably withheld.  Any attempted or purported Sublet
without Landlord's prior written consent shall be void and confer no rights upon
any third person and, at Landlord's election, shall terminate this Lease.  Each
Subtenant shall agree in writing, for the benefit of Landlord, to assume, to be
bound by, and to perform the terms, conditions and covenants of this Lease to be
performed by Tenant, as such terms, conditions and covenants apply to the Sublet
premises.  Notwithstanding anything contained herein, Tenant shall not be released
from liability for the performance of each term, condition and covenant of this
Lease by reason of Landlord's consent to a Sublet unless Landlord specifically grants
such release in writing.
 
           B.   Tenant's Notice.  If Tenant desires at any time to Sublet all or
                ---------------                                                
 any portion of the Premises, Tenant shall first notify Landlord in writing of its
desire to do so.
 
           C.   Information to be Furnished.  If Tenant desires at any time to
                ---------------------------                                    Sublet
all or any portion of the Premises, then Tenant shall submit in writing to Landlord:
(i) the name of the proposed Subtenant; (ii) the nature of the proposed Subtenant's
business to be carried on in the 
 
                                       38 

 Premises; (iii) the terms and provisions of the proposed Sublet and a copy of the
proposed form of Sublet agreement containing a description of the subject premises;
and (iv) such financial information, including financial statements, as Landlord
may reasonably request concerning the proposed Subtenant.
 
           D.   Landlord's Alternatives.  At any time within ten (10) days after
                -----------------------                                        
 Landlord's receipt of the information specified in Paragraph 25.C., Landlord
                                                    ---------------           may,
by written notice to Tenant, elect: (i) to consent to the Sublet by Tenant; or (ii)
to refuse its consent to the Sublet. If Landlord consents to the Sublet, Tenant
may thereafter enter into a valid Sublet of the Premises or applicable portion thereof,
upon the terms and conditions and with the proposed Subtenant set forth in the information
furnished by Tenant to Landlord, subject, however, at Landlord's election, to the
condition that the following percentages of any excess of the Subrent (the "Excess
Subrent") over the Rent required to be paid
                             --------------                                    
by Tenant under this Lease (or, if only a portion of the Premises is Sublet, the
pro rata share of the Rent attributable to the portion of the Premises being Sublet)
less reasonable attorneys' fees, leasing commissions, improvement costs required
for such Sublet (which shall not include the cost of any trade fixtures, equipment
or personal property) and other reasonable subletting costs paid by Tenant on the
Sublet, shall be paid to Landlord.  Tenant shall pay the following percentages of
Excess Subrent to Landlord in the following circumstances: (i) to the extent the
Excess Subrent (for the entire term of the applicable Sublet) is payable on a monthly
basis (as opposed to one or more lump sums) and to the extent the Excess Subrent
is less than or equal to $0.25/month/square foot of Rentable Area of the portion
of the Premises being Sublet, then Tenant shall pay to Landlord one-third (1/3)
of the Excess Subrent; (ii) to the extent the Excess Subrent (for the entire term
of the applicable Sublet) is payable on a monthly basis (as opposed to one or more
lump sums) and to the extent the Excess Subrent is greater than $0.25/month/square
foot of Rentable Area of the portion of the Premises being Sublet, then Tenant shall
pay to Landlord fifty percent (50%) of the Excess Subrent; (iii) to the extent the
Excess Subrent (for the entire term of the applicable Sublet) is not payable on
a monthly basis, then Tenant shall pay to Landlord fifty percent (50%) of the Excess
Subrent; and (iv) to the extent the Excess Subrent is applicable to any period during
an Extended Term, then Tenant shall pay to Landlord fifty percent (50%) of the Excess
Subrent.
 
           E.   Proration.  If a portion of the Premises is Sublet, the pro rata
                ---------                                                      
 share of the Rent attributable to such partial area of the Premises shall be determined
by Landlord by dividing the Rent payable by Tenant hereunder by the total square
footage of the Premises and multiplying the resulting quotient (the per square foot
rent) by the number of square feet of the Premises which are Sublet.
 
           F.   Parameters of Landlord's Consent.  Landlord shall have the right
                --------------------------------                               
 to base its consent to any Sublet hereunder upon such factors and considerations
as Landlord reasonably deems relevant or material to the proposed Sublet and the
best interests of the Project's operations.  Without limiting the generality of
the foregoing, Tenant acknowledges that it shall be reasonable for Landlord to withhold
its consent to any Sublet hereunder if Tenant has not demonstrated that: (i) the
proposed Subtenant is financially responsible, with sufficient net worth and net
current assets, properly and successfully to operate its business in the Premises
and meet the financial and other obligations of this Lease; (ii) the proposed Subtenant
possesses sound and 
 
                                       39 

 good business judgment, reputation and experience, and proven management skills
in the operation of a business or businesses substantially similar to the uses permitted
in the Premises under Paragraph 11.A; and (iii) the use of the
                                 --------------   Premises proposed by such Subtenant
conforms to the permitted uses specified under Paragraph 11.a, and involves either
no Hazardous Use or only such
       --------------               Hazardous Use as shall be acceptable to Landlord
in its sole discretion.
 
           G.   Permitted Transfers.  Notwithstanding the provisions of Paragraph
                -------------------                                     ---------
25.A above, Tenant shall have the right to enter into a Sublet, and Landlord - ----
                                                                        shall not
withhold its consent thereto (provided that all of the conditions set forth in clauses
(A) and (B) below shall be met), if such Sublet is one of the following "Permitted
Transfers": (i) a Sublet to the surviving entity of a merger or consolidation involving
the corporate entity constituting the Tenant under this Lease; or (ii) a Sublet
to any subsidiary or Affiliate of the Tenant originally named in this Lease.  However,
the foregoing Permitted Transfers shall be exempt from the requirement of Landlord's
consent only if all of the following conditions shall be met: (A) there shall be
no change in the use or operation of the Premises; (B) Tenant shall have provided
to Landlord all information to allow Landlord to determine, and Landlord shall have
determined, that the proposed transfer is a Permitted Transfer which is exempt from
the requirement of Landlord's consent; and (C) as of the effective date of such
Sublet, the proposed Subtenant has a net worth and net current assets equal to or
greater than those of the original Tenant under this Lease as of the date of this
Lease.  No Sublet of the type described in this Paragraph 25.G, nor any other transfer
of all or any portion of Tenant's interest in the Lease or the Premises, shall release
Tenant of its obligations under this Lease.
 
      26.  Default.
           ------- 
 
           A.   Tenant's Default.  A default under this Lease by Tenant shall
                ----------------                                              exist
if any of the following occurs:
 
                (i)   If Tenant fails to pay within five (5) days after written
notice from Landlord any Rent or any other sum required to be paid hereunder when
due, including, without limitation, any Tenant Improvement costs payable by Tenant
under Exhibit B; or
              ---------    
 
                (ii)  If Tenant fails to perform any term, covenant or condition
of this Lease except those requiring the payment of money, and Tenant fails to cure
such breach within thirty (30) days after written notice from Landlord where such
breach could reasonably be cured within such 30-day period; provided, however, that
where such failure could not reasonably be cured within the 30-day period, that
Tenant shall not be in default if it commences such performance within the 30-day
period and diligently thereafter prosecutes the same to completion; or
 
                (iii) If Tenant assigns its assets for the benefit of its creditors;
or
 
                (iv)  If the sequestration or attachment of or execution on any
material part of Tenant's Personal Property essential to the conduct of Tenant's
business occurs, and Tenant fails to obtain a return or release of such Tenant's
Personal Property within thirty (30) days 
 
                                       40 

 thereafter, or prior to sale pursuant to such sequestration, attachment or levy,
whichever is earlier; or
 
                (v)   If Tenant vacates or abandons the Premises; or
 
                (vi)  If a court makes or enters any decree or order other than
under the bankruptcy laws of the United States adjudging Tenant to be insolvent;
or approving as properly filed a petition seeking reorganization of Tenant; or directing
the winding up or liquidation of Tenant and such decree or order shall have continued
for a period of sixty (60) days; or
 
                (vii) If Tenant fails to cure within any applicable grace period
any default by Tenant under any of the Collateral Agreements.
 
           B.   Remedies.  Upon a default, Landlord shall have the following
                --------                                                     remedies,
in addition to all other rights and remedies provided by law or otherwise provided
in this Lease, to which Landlord may resort cumulatively or in the alternative:
 
                (i)   Landlord may continue this Lease in full force and effect,
and this Lease shall continue in full force and effect as long as Landlord does
not terminate this Lease, and Landlord shall have the right to collect Rent when
due. Without limiting the foregoing, Landlord has the remedy set forth in Section
1951.4 of the California Civil Code.
 
                (ii)  Landlord may terminate Tenant's right to possession of the
Premises at any time by giving written notice to that effect, and relet the Premises
or any part thereof.  Tenant shall be liable immediately to Landlord for all costs
Landlord incurs in reletting the Premises or any part thereof, including, without
limitation, broker's commissions, expenses of cleaning and redecorating the Premises
required by the reletting and like costs.  Reletting may be for a period shorter
or longer than the remaining Term of this Lease. No act by Landlord other than giving
written notice of termination to Tenant shall terminate this Lease. Neither acts
of maintenance, nor efforts to relet the Premises, nor the appointment of a receiver
on Landlord's initiative to protect Landlord's interest under this Lease shall not
constitute a termination of Tenant's right to possession.  On termination, Landlord
has the right to remove all Tenant's Personal Property and store the same at Tenant's
sole cost and expense and to recover from Tenant as damages:
 
                          (a)  The worth at the time of award of the unpaid Rent
and other sums due and payable which had been earned at the time of termination;
plus
 
                          (b)  The worth at the time of award of the amount by which
the unpaid Rent and other sums due and payable which would have been payable after
termination until the time of award exceeds the amount of such Rent loss that Tenant
proves could have been reasonably avoided; plus
 
                          (c)  The worth at the time of award of the amount by which
the unpaid rent and other sums due and payable for the balance of the Term after
the time of award
 
                                       41 

 exceeds the amount of such Rent loss that Tenant proves could be reasonably avoided;
plus
 
                      (d)  Any other amount necessary to compensate Landlord for
all the detriment proximately caused by Tenant's failure to perform Tenant's obligations
under this Lease, or which, in the ordinary course of things, would be likely to
result therefrom, including, without limitation, any costs or expenses incurred
by Landlord: (i) in retaking possession of the Premises; (ii) in maintaining, repairing,
preserving, restoring, replacing, cleaning, altering or rehabilitating the Premises
or any portion thereof, including such acts for reletting to a new tenant or tenants;
(iii) for leasing commissions; or (iv) for any other costs necessary or appropriate
to relet the Premises; plus
 
                      (e)  At Landlord's election, such other amounts in addition
to or in lieu of the foregoing as may be permitted from time to time by the laws
of the State of California.
 
           The "worth at the time of award" of the amounts referred to in Paragraphs
26.B.(ii)(a) and 26.B.(ii)(b) is computed by allowing interest at the - -----------------------
    ------------                                         Interest Rate on the unpaid
rent and other sums due and payable from the termination date through the date of
award.  The "worth at the time of award" of the amount referred to in Paragraph
26.B.(ii)(c) is computed by discounting such
                           ----------------------                              
  amount at the discount rate of the Federal Reserve Bank of San Francisco at the
time of award plus one percent (1%).  Tenant waives redemption or relief from forfeiture
under California Code of Civil Procedure Sections 1174 and 1179, or under any other
present or future law, in the event Tenant is evicted or Landlord takes possession
of the Premises by reason of any default of Tenant hereunder.
 
                (iii) Landlord may, with or without terminating this Lease, re-
enter the Premises and remove all persons and property from the Premises; such property
may be removed and stored in a public warehouse or elsewhere at the cost of and
for the account of Tenant. No reentry or taking possession of the Premises by Landlord
pursuant to this Paragraph 26.B.(iii) shall be construed as an election to terminate
this Lease unless a written notice of such intention is given to Tenant.
 
           C.   Landlord's Default.  Landlord shall not be deemed to be in
                ------------------                                         default
in the performance of any obligation required to be performed by it hereunder unless
and until it has failed to perform such obligation within thirty (30) days after
receipt of written notice by Tenant to Landlord specifying the nature of such default;
provided, however, that if the nature of Landlord's obligation is such that more
than thirty (30) days are required for its performance, then Landlord shall not
be deemed to be in default if it shall commence such performance within such 30-day
period and thereafter diligently prosecute the same to completion.
 
      27.  Subordination.
           ------------- 
 
           A.   Subordination.  This Lease is or may become subject and
                -------------                                           subordinate
to underlying leases, mortgages, deeds of trust, easements, and CC&Rs (collectively,
"Encumbrances") which may now or hereafter affect the
                       ------------                                         Premises,
and to all renewals, 
 
                                        42 

 amendments, modifications, consolidations, replacements and extensions thereof;
provided, however, if the holder or holders of any such Encumbrance (collectively,
"Holder") shall require that this Lease be prior and superior
                 ------ thereto, within fifteen (15) days of written request of
Landlord to Tenant, Tenant shall execute, have acknowledged and deliver any and
all documents or instruments, in the form presented to Tenant, which Landlord or
Holder deems reasonably necessary or desirable for such purposes. Subject to Paragraph
27.C
                                                                 --------------
 below, Landlord shall have the right to cause this Lease to be and become and remain
subject and subordinate to any and all Encumbrances which are now or may hereafter
be executed covering the Premises or any renewals, modifications, consolidations,
replacements or extensions thereof, for the full amount of all advances made or
to be made thereunder and without regard to the time or character of such advances,
together with interest thereon and subject to all the terms and provisions thereof;
provided only, that in the event of termination of any such lease or upon the foreclosure
of any such mortgage or deed of trust, so long as Tenant is not in default, Holder
agrees to recognize Tenant's rights under this Lease as long as Tenant shall pay
the Rent and observe and perform all the provisions of this Lease to be observed
and performed by Tenant. Within fifteen (15) days after Landlord's written request,
Tenant shall execute any and all documents reasonably required by Landlord or the
Holder to make this Lease subordinate to any lien of the Encumbrance (including,
without limitation, subordination to all CC&Rs), including without limitation a
Subordination, Non-Disturbance and Attornment Agreement in the form attached hereto
as Exhibit E ("SNDA"). Subject to Paragraph 27.C below, if
                    ---------   ----               --------------           Tenant
fails to do so, such failure shall constitute a default under this Lease, and it
shall be deemed that this Lease is subordinated to such Encumbrance.
 
           B.   Attornment.  Notwithstanding anything to the contrary set forth
                ----------                                                     
in this Paragraph 27, Tenant hereby attorns and agrees to attorn to any entity
         ------------                                                          
purchasing or otherwise acquiring the Premises at any sale or other proceeding or
pursuant to the exercise of any other rights, powers or remedies under such Encumbrance;
provided only, that so long as Tenant is not in default, any such purchasing or
acquiring entity agrees to recognize Tenant's rights under this Lease as long as
Tenant shall pay the Rent and observe and perform all the provisions of this Lease
to be observed and performed by Tenant.
 
           C.   Non-Disturbance.  Notwithstanding anything to the contrary in
                ---------------                                               this
Lease, if an Encumbrance, other than any CC&R's or Landlord's construction loan,
is created after the execution of this Lease, as a condition to the subordination
of this Lease thereto under Paragraph 27.A above, Landlord shall
                                           --------------                      
obtain from the Holder of such Encumbrance, other than CC&R's or the Holder of the
construction loan, a SNDA in a form reasonably requested by such Holder. Without
in any way limiting the type or form of SNDA that may be required by such Holder,
Tenant hereby agrees that a SNDA in the form attached to this Lease as Exhibit G
shall be reasonable.  Only upon Landlord's delivery of a SNDA in
    ---------                                                                  the
form of Exhibit G or in a form reasonably requested by the Holder, shall this Lease
be automatically subject and subordinate to such Encumbrance, other than CC&R's
or the construction loan.
 
      28.  Notices.
           ------- 
 
           Any notice or demand required or desired to be given under this Lease
shall be in 
 
                                        43 

 writing and shall be personally served or in lieu of personal service may be given
by certified mail, facsimile, or overnight courier service. All notices or demands
under this Lease shall be deemed given, received, made or communicated on the date
personal delivery is effected; or, if sent by certified mail, on the delivery date
or attempted delivery date shown on the return receipt; or, if sent by facsimile,
on the date sent by the sender; or, if sent by overnight courier service, on the
delivery date or attempted delivery date shown on such service's records. At the
date of execution of this Lease, the addresses of Landlord and Tenant are as set
forth in Paragraph 1. Either party may change its address by giving notice of same
in accordance with this Paragraph 28.
 
      29.  Attorneys' Fees.
           --------------- 
 
           If either party brings any action or legal proceeding for damages for
an alleged breach of any provision of this Lease, to recover Rent, or other sums
due, to terminate the tenancy of the Premises or to enforce, protect or establish
any term, condition or covenant of this Lease or right of either party, the prevailing
party shall be entitled to recover as a part of such action or proceedings, or in
a separate action brought for that purpose, reasonable attorneys' fees and costs,
including without limitation any and all costs and expenses arising from (i) collection
efforts, (ii) any appellate proceedings, and (iii) any bankruptcy, insolvency or
arbitration proceedings.
 
      30.  Estoppel Certificates.
           --------------------- 
 
           Tenant shall within fifteen (15) days following written request by Landlord:
 
                (i)  Execute and deliver to Landlord any documents, including estoppel
certificates, in the form prepared by Landlord (a) certifying that this Lease is
unmodified and in full force and effect or, if modified, stating the nature of such
modification and certifying that this Lease, as so modified, is in full force and
effect and the date to which the Rent and other charges are paid in advance, if
any, and (b) acknowledging that there are not, to Tenant's knowledge, any uncured
defaults on the part of Landlord, or, if there are uncured defaults on the part
of the Landlord, stating the nature of such uncured defaults, (c) evidencing the
status of the Lease as may be required either by a lender making a loan to Landlord
to be secured by deed of trust or mortgage covering the Premises or a purchaser
of the Premises from Landlord, and (d) such other matters as may be reasonably requested
by Landlord. Tenant's failure to deliver an estoppel certificate within fifteen
(15) days after delivery of Landlord's written request therefor shall be conclusive
upon Tenant (a) that this Lease is in full force and effect, without modification
except as may be represented by Landlord, (b) that there are now no uncured defaults
in Landlord's performance, and (c) that no Rent has been paid in advance.
 
           If Tenant fails to so deliver a requested estoppel certificate within
the prescribed time it shall be conclusively presumed that this Lease is unmodified
and in full force and effect except as represented by Landlord.
 
                (ii)  Deliver to Landlord the current financial statements of Tenant,
and
 
                                       44 

 financial statements of the two (2) years prior to the current financial statements
year, with an opinion of a certified public accountant, including a balance sheet
and profit and loss statement for the most recent prior year, all prepared in accordance
with generally accepted accounting principles consistently applied.
 
      31.  Transfer of the Premises by Landlord.
           ------------------------------------ 
 
           In the event of any conveyance of the Premises and assignment by Landlord
of this Lease, Landlord shall be and is hereby entirely released from all liability
under any and all of its covenants and obligations contained in or derived from
this Lease occurring after the date of such conveyance and assignment, and Tenant
agrees to attorn to such transferee provided such transferee assumes Landlord's
obligations under this Lease.
 
      32.  Landlord's Right to Perform Tenant's Covenants.
           ---------------------------------------------- 
 
           If Tenant shall at any time fail to make any payment or perform any other
act on its part to be made or performed under this Lease, and such failure shall
continue after the expiration of any applicable grace or cure periods provided in
this Lease, Landlord may, but shall not be obligated to (and without waiving or
releasing Tenant from any obligation of Tenant under this Lease), make such payment
or perform such other act to the extent Landlord may deem desirable, and in connection
therewith, pay expenses and employ counsel.  All sums so paid by Landlord and all
penalties, interest, expenses and costs in connection therewith shall be due and
payable by Tenant on the next day after any such payment by Landlord, together with
interest thereon at the Interest Rate from such date to the date of payment by Tenant
to Landlord, plus collection costs and attorneys' fees.  Landlord shall have the
same rights and remedies for the nonpayment thereof as in the case of default in
the payment of Rent.
 
      33.  Tenant's Remedy.
           --------------- 
 
           Landlord shall never be personally liable under this Lease, and Tenant
shall look solely to the net cash flow received by Landlord from its ownership of
the Building, for recovery of any damages for breach of this Lease by Landlord or
on any judgment in connection therewith.  None of the persons or entities comprising
or representing Landlord (whether partners, shareholders, officers, directors, trustees,
employees, beneficiaries, agents or otherwise) shall ever be personally liable under
this Lease or for any such damages or judgment, and Tenant shall have no right to
effect any levy of execution against any assets of such persons or entities on account
of any such liability or judgment.  Any lien obtained by Tenant to enforce any such
judgment, and any levy of execution thereon, shall be subject and subordinate to
all Encumbrances as specified in Paragraph 27 above.
                 ------------       
 
      34.  Mortgagee Protection.
           -------------------- 
 
           If Landlord defaults under this Lease, Tenant shall give written notice
of such default to any beneficiary of a deed of trust or mortgagee of a mortgage
covering the Premises, and offer such beneficiary or mortgagee a reasonable opportunity
to cure the default, including 
 
                                       45 

 time to obtain possession of the Premises by power of sale or a judicial foreclosure,
if such should prove necessary to effect a cure.
 
      35.  Brokers.
           ------- 
 
           Landlord and Tenant acknowledge and agree that they have utilized the
services of real estate brokers (with AMB Corporate Real Estate Advisors and Colliers
Parrish representing Tenant, and BT Commercial representing Landlord) with respect
to the transactions between Landlord and Tenant that are represented by this Lease.
 Tenant warrants and represents that it has had no dealings with any other real
estate broker or agent in connection with the negotiation of this Lease, and that
it knows of no other real estate broker or agent who is or might be entitled to
a commission in connection with this Lease. Tenant shall indemnify, defend and hold
Landlord harmless from and against any and all claims, causes of action, liability
or costs, including reasonable attorney's fees, arising as a result of a breach
of the foregoing warranty and representation.  Nothing contained in this Paragraph
35 shall be deemed to
                                            ------------                    obligate
or require Landlord to pay any commission whatsoever to any real estate broker (including
without limitation AMB and BT) with respect to this Lease; the payment of any such
commission (if any) shall be governed by a separate written agreement between Landlord
and the real estate broker or brokers in question. Tenant shall separately compensate
AMB and Colliers Parrish for its services and no commission shall be payable to
AMB and Colliers Parrish in connection with this Lease.
 
      36.  Acceptance.
           ---------- 
 
           This Lease shall only become effective and binding upon full execution
hereof by Landlord and delivery of a signed copy to Tenant.  Neither party shall
record this Lease nor a short form memorandum thereof.
 
      37.  Parking.
           ------- 
 
           Tenant shall have the non-exclusive right, in common with any other tenants
or occupants of the Project, to use up to 3.33 unassigned parking spaces per each
one thousand (1,000) square feet of Rentable Area in the Premises, upon terms and
conditions, as may from time to time be reasonably established by Landlord; provided,
however, that Tenant acknowledges and agrees that during the construction of the
Parking Structure (as defined in the Build to Suit Agreement), the parking ratio
for the Building may from time to time be less than 3.33 spaces per 1,000 square
feet of Rentable Area. Should parking charges or surcharges of any kind be imposed
on the parking facilities by a governmental agency, Tenant shall reimburse Landlord
for such charges and/or surcharges or, if possible, shall pay such charges and/or
surcharges directly to the governmental agency and, in such event, Tenant shall
provide Landlord with proof that such charges and/or surcharges have been paid by
Tenant.  Parking on that portion of the Project cross-hatched on Exhibit C shall
be subject such
                                         ---------                       reciprocal
easement agreements affecting the such portion of the Project as Landlord may adopt
from time to time.
 
      38.  Right of First Offer to Purchase.
           -------------------------------- 
 
                                       46 
 
           During the term of this Lease, Landlord shall not sell fee title to the
Building to any unaffiliated third party or parties, without first offering to sell
the Building to Tenant upon the terms, covenants and conditions set forth in this
Paragraph 38; provided, however, that as provided below this
               ------------                                                 Paragraph
38 may cease to be of any force or effect prior to the expiration or - ------------
                                                                  earlier termination
of the term of this Lease. Notwithstanding any provision of this Lease to the contrary,
the provisions of this Paragraph 38 shall not apply
                                                    ------------               
 to, and Tenant shall have absolutely no rights in connection with, any of the following:
(i) any and all transfers of all or any portion of the Building, or any interest
therein, by means of judicial foreclosure, trustee's sale, deed in lieu of foreclosure
or similar conveyance, (ii) any and all transfers or conveyances of any ownership
interests in Landlord or any of the parties or entities comprising Landlord (including
without limitation transfers of partnership interests, membership interests, and
shares of common and/or preferred stock), (iii) any and all transfers of tenancy-in-common
interests in the Building by Landlord to, or by and among, the parties or entities
comprising Landlord, (iv) the creation of any liens, encumbrances or security interests
or the transfer of any interest in the Building for security purposes, and (v) the
transfer of all or any portion of the Building, or any interest in the Building,
to any Affiliate of Landlord or any partner, member or shareholder of Landlord.
 
           A.   Notice of Sale.  If at any time during the term of this Lease
                --------------                                                Landlord
desires to sell fee title to the Building to an unaffiliated third party, Landlord
shall give written notice to Tenant specifying the terms, covenants and conditions
upon which Landlord is willing to sell the Building (the "Acceptable Sale Terms").
 The notice shall constitute an irrevocable offer
       ---------------------                                                   
  on the part of Landlord (subject to the conditions described in Paragraph 38.F
                                                                 --------------
below) to sell the Building to Tenant upon the Acceptable Sale Terms, and Landlord
and Tenant shall have a period of thirty (30) days after Landlord's delivery of
the notice within which to negotiate and agree upon the terms and conditions for
the sale to Tenant of the Building (the "Sale Negotiation
                                                         ---------------- Period").
- ------
 
           B.   Acceptance.  If Tenant is interested in acquiring the Building,
                ----------                                                     
Tenant shall give Landlord written notice of such interest ("Notice of Interest
                                                              ------------------
I") within ten (10) days of Tenant's receipt of Landlord's notice (the "Purchase
- -                                                                       --------
Response Period"), and Landlord and Tenant shall proceed to negotiate Tenant's -
---------------                                                                purchase
of the Building and the terms and conditions of purchase during the Sale Negotiation
Period.  Should the parties reach agreement on the terms and conditions of Tenant's
acquisition of the Building within the Sale Negotiation Period, then Tenant shall
acquire, on an all cash basis, in the manner set forth in Paragraph 38.G, fee title
to the Building, together with any and all
    --------------                                                       improvements
situated thereon. Failure on the part of Tenant either to deliver a Notice of Interest
to Landlord within the Purchase Response Period or to accept Landlord's offer to
sell the Building within the Sale Negotiation Period shall each constitute Tenant's
rejection of Landlord's offer to sell the Building.
 
           C.   Rejection.  If (i) Tenant informs Landlord within the Sale
                ---------                                                  Response
Period that Tenant does not desire to negotiate the acquisition of the Building,
or (ii) after commencing negotiations, Landlord and Tenant do not reach agreement
upon the terms and conditions of Tenant's purchase of the Building within the Sale
Negotiation Period, or (iii) Tenant otherwise rejects Landlord's offer to sell the
Building, then, in any such event (except as provided to the contrary in Paragraphs
38.D and 38.E), this Paragraph 38 shall
                             ---------------     ----        ------------      
no longer apply to the Building, 
 
                                       47 

 and Landlord (and each and every subsequent owner of the Building) shall be free
to offer to sell all or any portion of the Building (separately or together with
any other parcel or parcels) to any third party or parties upon any terms whatsoever,
including without limitation terms less favorable to Landlord than the Acceptable
Sale Terms, without first offering the Building to Tenant.
 
           D.   Offered Terms.  If Tenant does not accept Landlord's offer as set
                -------------                                                  
  forth above, but Tenant does deliver to Landlord within the Sale Negotiation Period
a written offer ("Tenant's Purchase Offer") to acquire the Building for a
                          -----------------------                              
  purchase price ("Tenant's Offered Price") less than the price contained in the
                  ----------------------                                       
Acceptable Sale Terms, then Tenant shall be deemed to have made an irrevocable offer
to acquire the Building at Tenant's Offered Price. Tenant's Purchase Offer shall
be deemed to include all of the Acceptable Sale Terms, except that to the extent
there is any discrepancy between the Acceptable Sale Terms and the terms set forth
in Tenant's Purchase Offer, Tenant's Purchase Offer shall be controlling (except
as otherwise provided in Paragraph 38.G below).
                                              --------------        
 
           E.   Acceptance of Tenant's Offer.  If Tenant rejects or otherwise
                ----------------------------                                  fails
to accept Landlord's offer pursuant to this Paragraph 38 but delivers
                                                   ------------              Tenant's
Purchase Offer to Landlord in accordance with Paragraph 38.D, then
                                                        --------------       Landlord
may at any time within sixty (60) days after Landlord's receipt of Tenant's Purchase
Offer, accept Tenant's Purchase Offer and sell the Building to Tenant in accordance
with the terms thereof and the other terms and conditions set forth in this Paragraph
38.  If Landlord thus accepts Tenant's Purchase
                   ------------                                              Offer,
then Tenant shall acquire, on an all cash basis, in accordance with the provisions
of Paragraph 38.G, fee title to the Building, together with the
               --------------                                               improvements
situated thereon.  If Landlord does not accept Tenant's Purchase Offer within such
60-day period, then upon the expiration of such 60-day period this Paragraph 38
shall terminate and shall no longer apply to the Building, and
      ------------                                                             
  Landlord (and each and every subsequent owner of the Building) shall be free to
sell all or any portion of the Building (separately or together with any other parcel
or parcels) to a third party or parties upon any terms whatsoever, including without
limitation terms less favorable to Landlord than the terms contained in Tenant's
Purchase Offer, without first offering to sell the Building to Tenant.
 
           F.   Conditions.  The effectiveness of Tenant's right to offer to
                ----------                                                   acquire
any Building, as set forth in this Paragraph 38, is conditioned on the
                                            ------------                       
following: (i) Tenant has not previously entered into a Sublet of this Lease (other
than a Permitted Transfer); and (ii) no monetary or other material default by Tenant
exists under this Lease which remains uncured after the giving of any applicable
notice and the expiration of any applicable cure period.  In addition, if any of
the conditions specified under clauses (i) and (ii) above do not continue to be
satisfied as of the date on which the escrow for the sale of the Building to Tenant
is scheduled to close, then unless Landlord waives in writing any such conditions,
Tenant's exercise of its right to acquire the Building under this Paragraph 38 shall
be null and void, and this Lease shall
                     ------------                                              terminate
effective as of the date on which the escrow for the sale of the Building to Tenant
was scheduled to close.
 
           G.   Process.  In the event that Landlord and Tenant reach agreement
                -------                                                        
on the terms and conditions of the sale of the Building within the applicable period
of time set forth in 
 
                                       48 

 this Paragraph 38, Tenant's acquisition of the Building shall be carried out on
      ------------                              (i) the terms and conditions described
in this Paragraph 38 and/or to which
                                                ------------ Landlord and Tenant
have otherwise specifically agreed pursuant to this Paragraph 38 (collectively,
the "Agreed Terms"), and (ii) the terms and  - ------------                    
------------        conditions set forth on Exhibit F attached to this Lease (the
"Standard Terms
                         ---------                              -------------- for
Purchase").  To the extent there is any discrepancy between the Agreed - ------------
Terms and the Standard Terms, the Agreed Terms shall be controlling; provided, however,
that notwithstanding the foregoing, Tenant shall be required to make an earnest
money deposit equal to five percent (5%) of the purchase price for the Building,
pursuant to the Standard Terms.
 
           H.   Rights Personal.  The rights granted to Tenant under this
                ---------------                                           Paragraph
38 shall be personal to Tenant, and shall not be assigned, sold, - ------------
                                                              conveyed or otherwise
transferred to any other party (including without limitation any assignee or sublessee
of Tenant) without the prior written consent of Landlord, which consent may be withheld
in Landlord's sole discretion; provided, however, that the rights granted to Tenant
under this
                                                                             Paragraphs
38 may be transferred without Landlord's consent to the transferee of - -------------
                                                                   Tenant's interest
in this Lease pursuant to a Permitted Transfer.
 
      39.  General.
           ------- 
 
           A.   Captions.  The captions and headings used in this Lease are for
                --------                                                       
the purpose of convenience only and shall not be construed to limit or extend the
meaning of any part of this Lease.
 
           B.   Executed Copy.  Any fully executed copy of this Lease shall be
                -------------                                                  deemed
an original for all purposes.
 
           C.   Time.  Time is of the essence for the performance of each term,
                ----                                                           
condition and covenant of this Lease.
 
           D.   Separability.  If one or more of the provisions contained herein,
                ------------                                                   
  except for the payment of Rent, is for any reason held invalid, illegal or unenforceable
in any respect, such invalidity, illegality, or unenforceability shall not affect
any other provision of this Lease, but this Lease shall be construed as if such
invalid, illegal or unenforceable provision had not been contained herein.
 
           E.   Choice of Law.  This Lease shall be construed and enforced in
                -------------                                                 accordance
with the laws of the State of California. The language in all parts of this Lease
shall in all cases be construed as a whole according to its fair meaning and not
strictly for or against either Landlord or Tenant.
 
           F.   Gender; Singular, Plural.  When the context of this Lease
                ------------------------                                  requires,
the neuter gender includes the masculine, the feminine, a partnership or corporation
or joint venture, and the singular includes the plural.
 
           G.   Binding Effect.  The covenants and agreement contained in this
                --------------                                                 Lease

 
                                       49 

 shall be binding on the parties hereto and on their respective successors and assigns
to the extent this Lease is assignable.
 
           H.   Waiver.  The waiver by Landlord of any breach of any term,
                ------                                                     condition
or covenant, of this Lease shall not be deemed to be a waiver of such provision
or any subsequent breach of the same or any other term, condition or covenant of
this Lease.  The subsequent acceptance of Rent hereunder by Landlord shall not be
deemed to be a waiver of any preceding breach at the time of acceptance of such
payment.  No covenant, term or condition of this Lease shall be deemed to have been
waived by Landlord unless such waiver is in writing signed by Landlord.
 
           I.   Entire Agreement.  This Lease is the entire agreement between the
                ----------------                                               
  parties, and there are no agreements or representations between the parties except
as expressed herein. Except as otherwise provided herein, no subsequent change or
addition to this Lease shall be binding unless in writing and signed by the parties
hereto.
 
           J.   Authority.  If Tenant is a corporation or a partnership, each
                ---------                                                     individual
executing this Lease on behalf of said corporation or partnership, as the case may
be, represents and warrants that he is duly authorized to execute and deliver this
Lease on behalf of said entity in accordance with its corporate bylaws, statement
of partnership or certificate of limited partnership, as the case may be, and that
this Lease is binding upon said entity in accordance with its terms.  Landlord,
at its option, may require a copy of such written authorization to enter into this
Lease.
 
           K.   Exhibits.  All exhibits, amendments, riders and addenda attached
                --------                                                       
 hereto are hereby incorporated herein and made a part hereof.
 
           L.   Lease Summary.  The Lease Summary attached to this Lease is
                -------------                                               intended
to provide general information only.  In the event of any inconsistency between
the Lease Summary and the specific provisions of this Lease, the specific provisions
of this Lease shall prevail.
 
           M.   Memorandum of Lease.  This Lease shall not be recorded without
                -------------------                                            the
prior consent of both Landlord and Tenant; provided, however, that upon the written
request of Tenant, Landlord and Tenant shall execute and acknowledge, in recordable
form, a memorandum of this Lease in form reasonably acceptable to both Landlord
and Tenant, and shall cause such memorandum to be recorded in the Official Records
of the County of San Mateo, State of California. Upon expiration of the term of
this Lease or earlier termination of this Lease, Tenant shall execute, acknowledge
and deliver to Landlord an appropriate instrument prepared by Landlord which Landlord
may then record in the Official Records of San Mateo County to expunge this Lease
and any memorandum thereof from the public record with respect to the Premises.
In addition, Tenant hereby irrevocably constitutes and appoints Landlord as its
true and lawful attorney in fact, in its name and in its behalf, to make, execute,
acknowledge, deliver, and file any and all such instruments that Tenant so fails
or refuses to execute. Tenant expressly understands and acknowledges that the foregoing
special power of attorney is coupled with an interest, is irrevocable, and shall
survive the dissolution or insolvency of Tenant, or the transfer 
 
                                       50 

 by Tenant of the whole or any portion of its interest in this Lease (provided that
any such transfer shall be subject to the restrictions set forth in this Lease).
 
                                       51 
 
           THIS LEASE is effective as of the date the last signatory necessary to
execute the Lease shall have executed this Lease.
 
                                    TENANT:

 Dated:  July 7,1997                AT HOME CORPORATION,
                                    a Delaware corporation

 
                                    By:  /s/ Kenneth A. Goldman
                                         ------------------------------
                                    Its:  Chief Financial Officer
                                         ------------------------------
 
                                    By:   _____________________________
                                    Its:  _____________________________

 
                                    LANDLORD:

 Dated:  September 29, 1997         MARTIN/CAMPUS ASSOCIATES, L.P.,
                                    a Delaware limited partnership
 
                                    By:   Martin/Redwood Partners,
                                          L.P., a California limited
                                          partnership, its General
                                          Partner
 
                                          By:  The Martin Group of
                                               Companies, Inc., a
                                               California corporation,
                                               its General Partner

 
                                               By: /s/ Cathy Greenwold
                                                   --------------------
                                               Its:   Vice President
                                                   --------------------
 
                                       52 
 
                                    EXHIBIT A

 
                                  @HOME CAMPUS
 
                                  BUILDING A&B 
 
                                    EXHIBIT B
                                    ---------
 
                              WORK LETTER AGREEMENT
                              ---------------------
 
           THIS WORK LETTER ("Agreement") is made and entered into by and between
Landlord and Tenant as of the date of the Lease. This Agreement shall be deemed
a part of the Lease to which it is attached.  Capitalized terms which are used herein
and defined in the Lease shall have the meanings given in the Lease.
 
      1.   General.
           ------- 
 
           1.1  Capital Improvements.  Pursuant to the Build to Suit Agreement,
                --------------------                                           
Landlord shall construct the Shell and Core and applicable site work (as defined
in the Build to Suit Agreement) (collectively, the "Capital Improvements").
                                                     --------------------     Except
for its obligation to perform the Capital Improvements and the Tenant Improvements
as set forth in this Lease and the Work Letter, Landlord shall have no obligation
whatsoever to do any work or perform any improvements whatsoever to any portion
of the Premises or the Building; provided, however, that the Tenant Improvements
shall be performed at the sole cost and expense of Tenant (subject to the provisions
of Paragraph 1.4).  Landlord shall cause Contractor
                               -------------                                   
(as defined below) to perform all initial leasehold improvements, in accordance
with the approved Final Plans and as otherwise may be required to comply with applicable
law (collectively, the "Tenant Improvements").  The parties
                                    -------------------                 acknowledge
and agree that the Capital Improvements and the Tenant Improvements constitute all
of the work required to enable Tenant to occupy, and operate its business in, the
Premises.
 
           1.2  Tenant Improvement Costs.  The cost of performing the Tenant
                ------------------------                                     Improvements,
including without limitation the costs described in Paragraph 6
                                                                   ----------- below
(collectively, the "Tenant Improvement Costs") shall be paid by Tenant in
                           ------------------------                            
 the manner set forth in Paragraph 5 below, subject to the provisions of
                         -----------                                     Paragraph
1.4. - ------------- 
 
           1.3  Tenant Improvements Allowance.  If the lender for the
                -----------------------------                         Construction
Financing (as defined in the Build to Suit Agreement) is willing to increase the
amount of such Construction Financing to cover all or any portion of the Tenant
Improvement Costs, then Landlord shall provide an allowance for the Tenant Improvement
Costs in an amount equal to that portion of the Construction Financing budgeted
for payment of such costs (the "Tenant
                                                                 ------ Improvements
Allowance"); provided, however, that in no event shall the Tenant - ----------------------
                                                        Improvements Allowance exceed
Thirty Dollars ($30.00) per square foot of Rentable Area to be situated in the Building.
 
      2.   Approval of Plans for Tenant Improvements.
           ----------------------------------------- 
 
           2.1  Architect.  Within five (5) days after execution of the Lease,
                ---------                                                      Tenant
shall notify Landlord in writing of the name and address of the licensed architect
which Tenant desires to engage for the preparation of plans for Tenant's Work ("Architect").
 Tenant's proposed architect shall be subject to
                 ---------                                                     Landlord's
prior written approval. Tenant shall retain Architect's administrative services
throughout the performance of Tenant's Work.  Designers who are not  

 licensed architects will not be acceptable.
 
           2.2  Submittal of Plans.
                ------------------ 
 
                2.2.1.  Preliminary Plans.  Tenant shall cause Architect to 
                        -----------------            prepare preliminary plans (the
"Preliminary Plans") for the Tenant Improvements 
                                 -----------------                             
to be performed at the Premises. Tenant shall cause Architect to deliver the Preliminary
Plans to Landlord within thirty (30) days after the date on which the Lease has
been signed by Landlord and Tenant. Within five (5) days after Landlord's receipt
of the Preliminary Plans, Landlord shall either approve or disapprove the Preliminary
Plans, which approval shall not be unreasonably withheld. If Landlord disapproves
the Preliminary Plans, then Landlord shall state in reasonable detail the changes
which Landlord requires to be made thereto.  Tenant shall submit to Landlord revised
Preliminary Plans within five (5) days after Tenant's receipt of Landlord's disapproval
notice. Following Landlord's receipt of the revised Preliminary Plans from Tenant,
Landlord shall have the right to review and approve the revised Preliminary Plans
pursuant to this Paragraph 2.2.1.  Landlord shall give Tenant written notice of
its approval
      ---------------                                                          
  or disapproval of the revised Preliminary Plans within five (5) days after the
date of Landlord's receipt thereof.  If Landlord reasonably disapproves the revised
Preliminary Plans, then the following shall occur: (i) Landlord and Tenant shall
continue to follow the procedures set forth in this Paragraph 2.2.1
                                                                  ---------------
until Landlord and Tenant reasonably approve the Preliminary Plans in accordance
with this Paragraph 2.2.1, and (ii) the period between the date of Landlord's
           ---------------                                                     reasonable
disapproval and the eventual mutual approval of such Preliminary Plans shall constitute
a Tenant Delay.
 
                2.2.2.  Preliminary Budget.  Landlord shall retain a contractor
                        ------------------                                     
("Contractor") as the general contractor for the construction of the Tenant - ------------
                                                               Improvements. Tenant
shall have the right to approve the construction contract between Landlord and Contractor
for the construction of the Tenant Improvements, which approval shall not be unreasonably
withheld or delayed; provided, however, that Tenant shall have no right to disapprove
such construction contract if such construction contract substantially conforms
with the applicable AIA form contract and general conditions.  Ten (10) days after
approval by Landlord and Tenant of the Preliminary Plans, Contractor shall prepare
a preliminary budget for the Tenant Improvements based upon the approved Preliminary
Plans, which Contractor shall submit to Tenant for its review and approval.  Within
three (3) days after Tenant's receipt of the preliminary budget, Tenant shall either
approve or disapprove the preliminary budget.  If Tenant reasonably rejects such
preliminary budget, Tenant shall, within five (5) days of Tenant's delivery of a
written rejection notice to Landlord, require Architect to revise the Preliminary
Plans to reduce the cost of the Tenant Improvements.  Following Tenant's instructions
to the Architect, Landlord and Tenant shall again follow the procedures set forth
in Paragraph 2.2.1 and this Paragraph 2.2.2 with respect to the approval of the
Preliminary Plans and to the submission and approval of the preliminary budget from
Contractor.
 
                2.2.3.  Final Plans.  Within three (3) days after approval by 
                        -----------                 Landlord and Tenant of the preliminary
budget for the Tenant Improvements, Tenant shall cause Architect to commence preparing
complete plans, specifications and working drawings which incorporate and are consistent
with the approved Preliminary Plans and preliminary budget, and which show in detail
the intended design, construction and finishing of all portions of the Tenant Improvements
 

 described in the Preliminary Plans (collectively, the "Final Plans"). Tenant
                                                        ----------- shall cause
Architect to deliver the Final Plans to Landlord, for Landlord's review and approval,
no later than ninety (90) days after the date on which the Lease has been signed
by Landlord and Tenant. Within five (5) days after Landlord's receipt of the Final
Plans, Landlord shall either approve or disapprove the Final Plans, which approval
shall not be unreasonably withheld. If Landlord disapproves the Final Plans, then
Landlord shall state in reasonable detail the changes which Landlord requires to
be made thereto. Tenant shall submit to Landlord revised Final Plans within five
(5) days after Tenant's receipt of Landlord's disapproval notice. Following Landlord's
receipt of the revised Final Plans from Tenant, Landlord shall have the right to
review and approve the revised Final Plans pursuant to this Paragraph 2.2.3. Landlord
shall
                                                  --------------- give Tenant written
notice of its approval or disapproval of the revised Final Plans within five (5)
days after the date of Landlord's receipt thereof. If Landlord reasonably disapproves
the revised Final Plans, then the following shall occur: (i) Landlord and Tenant
shall continue to follow the procedures set forth in this Paragraph 2.2.3 until
Landlord and Tenant reasonably approve such Final Plans in accordance with this
Paragraph 2.2.3, and (ii) the period between
                                     --------------- the date of Landlord's reasonable
disapproval and the eventual mutual approval of such Final Plans shall constitute
a Tenant Delay.
 
           3.  Construction Budget.  Upon approval by Landlord and Tenant of the
               -------------------                                             
 Final Plans, Landlord shall instruct Contractor to obtain competitive bids for
the Tenant Improvements from at least three (3) qualified subcontractors for each
of the major subtrades (excluding the mechanical and electrical trades, which shall
be on a design/build basis, unless Landlord elects to competitively bid these trades)
and to submit the same to Landlord and Tenant for their review and approval.  Upon
selection of the subcontractors and approval of the bids, Contractor shall prepare
a cost estimate for the Tenant Improvements described in such Final Plans, based
upon the bids submitted by the subcontractors selected.  Contractor shall submit
such cost estimate to Landlord and Tenant for their review and approval. Within
five (5) days after their receipt of the cost estimate, Landlord and Tenant shall
each either approve or disapprove the cost estimate, which approval shall not be
unreasonably withheld. Tenant's failure to approve or disapprove the cost estimate
within such 5-day period shall constitute Grounds for the assertion of a Tenant
Delay.  Landlord or Tenant may each approve or reject such cost estimate in their
reasonable sole discretion. If either Landlord or Tenant rejects such cost estimate,
Landlord shall resolicit bids based on such Final Plans, in accordance with the
procedures specified above. Following any resolicitation of bids by Landlord pursuant
to this Paragraph 3, Landlord and Tenant shall again follow the procedures set
      -----------                                                            forth
in this Paragraph 3 with respect to the submission and reasonable approval
               -----------                                                     
  of the cost estimate from Contractor; provided, however that the period between
Tenant's disapproval of the first revised cost estimate and the eventual mutual
approval of a cost estimate shall constitute a Tenant Delay.
 
      4.   Landlord to Construct. Landlord shall cause Contractor to construct
           ---------------------                        the Tenant Improvements
in a good and workmanlike manner, in accordance with the approved Final Plans and
in compliance with all applicable laws. Architect shall be responsible for obtaining
all necessary building permits and approvals and other authorizations from governmental
agencies required in connection with the Tenant Improvements. The cost of all such
permits and approvals, including inspection and other building fees required to
obtain the permits for the Tenant Improvements, shall be included as part of the
Tenant Improvement Costs. Tenant shall have the benefit of any warranties provided
by Contractor, the subcontractors and suppliers in  

 connection with the Tenant Improvements.
 
      5.   Payment for Tenant Improvements. The Tenant Improvement Costs shall be
           -------------------------------              paid solely by Tenant as
follows:
 
           5.1  Method of Payment.  If Landlord provides a Tenant Improvements
                -----------------                                              Allowance
for the Building pursuant to Paragraph 1.4 above, Landlord shall bear
                                        --------------                         
 the Tenant Improvement Costs up to the amount of such Tenant Improvements Allowance;
and Tenant shall be responsible for paying any excess in the Tenant Improvement
Costs over the amount of such Tenant Improvements Allowance.  If Landlord does not
provide a Tenant Improvements Allowance, Tenant shall be solely responsible for
the payment of any and all Tenant Improvement Costs. For the purposes of this Exhibit
B, the term "Tenant's Share of Tenant Improvement
                      ---------            ------------------------------------
Costs" shall mean the entire amount of all Tenant Improvement Costs, less any -
-----                                                                         Tenant
Improvements Allowance provided by Landlord; provided, however, that if Landlord
does not provide a Tenant Improvements Allowance, then "Tenant's Share
                                                                  --------------
of Tenant Improvement Costs" shall mean the entire amount of all Tenant - ---------------------------
                                            Improvement Costs. If required by any
lender holding a security interest encumbering the land on which the Building will
be situated, Tenant shall provide the Set-Aside Funds (as defined in Paragraph 5.1.1)
in accordance with
                                            ---------------                    
the provisions of Paragraph 5.1.1.  If at the time construction of the Building
                   ---------------                                             
 is scheduled to commence no such lender exists, or if there is such a lender but
such lender does not at any time during the construction of the Building require
Landlord to obtain the Set-Aside Funds from Tenant, then Tenant shall not be required
to provide the Set-Aside Funds for the construction of the Building.
 
                5.1.1.  Set-Aside Funds. If Tenant is required to deposit the 
                        --------------- Set-Aside Funds pursuant to Paragraph 5.1,
then within five (5) days after the
                             -------------                                     
parties have mutually agreed upon a cost estimate for the Tenant Improvements as
provided above, Tenant shall deposit into a separate account with any financial
institution designated by Landlord, in Tenant's name, subject to restrictions in
favor of such financial institution, an amount (the "Set-Aside Funds") equal to
                                                      ---------------          
 (a) the entire amount of Tenant's Share of Tenant Improvement Costs, based on the
assumption that the Tenant Improvement Costs shall equal such cost estimate, and
(b) all other amounts to be deposited by Tenant in such account pursuant to the
terms of the Build to Suit Option Agreement.  Landlord shall instruct such financial
institution to hold the Set-Aside Funds in a separate interestbearing account with
interest to accrue for Tenant's account, and shall utilize the Set- Aside Funds
to pay for Tenant's Share of Tenant Improvement Costs and any other obligations
of Tenant pursuant to the Build to Suit Option Agreement.  Before commencement of
construction of any subsequent portion of the Tenant Improvements, Tenant shall
deposit in such account an additional amount equal to Tenant's Share of Tenant Improvement
Costs for such subsequent Tenant Improvements.
 
                5.1.2.  Payment. If Landlord provides a Tenant Improvements
                        ------- Allowance pursuant to Paragraph 1.4 above, then
within twenty (20) days after
                       ------------- Landlord's receipt of reasonably satisfactory
invoices for costs of labor and materials incurred in connection with the Tenant
Improvements, together with such supporting documentation and lien waivers as Landlord
may reasonably require in order to review the costs covered by the billing, Landlord
shall pay the Tenant Improvement Costs represented by such invoices first coming
due for 

 payment, up to an aggregate amount equal to the Tenant Improvements Allowance.
As and when any amount of Tenant's Share of Tenant Improvement Costs or any amounts
payable by Tenant pursuant to the Build to Suit Option Agreement become due and
payable, Landlord shall request such financial institution to utilize the remaining
SetAside Funds to pay such amounts; provided, however, that if at any time there
are insufficient Set-Aside Funds to pay any amount of Tenant's Share of Tenant Improvement
Costs and/or any other amounts payable by Tenant pursuant to the Build to Suit Option
Agreement, Tenant shall pay any and all such excess Shell and Core Costs and Tenant
Improvement Costs to Landlord within ten (10) days after the date of Tenant's receipt
of Landlord's written request therefor, together with such supporting documentation
and lien waivers as Tenant may reasonably require in order to review the costs covered
by the billing. Any failure by Tenant to pay any amount of Tenant's Share of Tenant
Improvement Costs or any other amounts payable by Tenant pursuant to the Build to
Suit Option Agreement as and when required under this Exhibit B shall constitute
a
                                                  ---------                    default
by Tenant under the Lease.
 
                5.1.3.  Penalties. To the extent that any contractor or
                        --------- subcontractor working on the Tenant Improvements
imposes upon Landlord any penalty or late charge due to Tenant's failure to pay
to Landlord any amount due under this Paragraph 5.1 as and when such amount is due,
Tenant shall be solely
            ------------- responsible for paying such penalty or late charge; provided,
however, that if Tenant disputes the imposition of such penalty or late charge,
Tenant shall not be required to pay the penalty or late charge until the dispute
has been settled or otherwise resolved; provided further, that if any penalty or
late charge is imposed due to Tenant's exercise of its rights under this Paragraph
5.1.3,
                                                           ---------------  Tenant
shall pay such penalty or late charge as provided in this Paragraph
                                                                  --------- 5.1.3.
- -----
 
           5.2  Extra Work.  Tenant shall be solely responsible for any and all
                ----------                                                     
costs and expenses arising from any improvements to or installations in the Building
desired by Tenant and approved by Landlord that are outside the scope of the Final
Plans.
 
      6.   Tenant Improvement Costs. The Tenant Improvement Costs shall include
           ------------------------              all reasonable costs incurred in
connection with the Tenant Improvements (but not the Capital Improvements), as determined
by Landlord in its reasonable discretion, including the following:
 
           (a)  All costs of space plans and other architectural and engineering
plans and specifications for the Tenant Improvements, including engineering costs
associated with completion of the State of California energy utilization calculations
under Title 24 legislation required in connection with the Tenant Improvements;
 
           (b)  All costs of obtaining building permits and other necessary authorizations
from the City of Redwood City;
 
           (c)  All costs of interior design and finish schedule plans and specifications,
including as-built drawings by Architect;
 
           (d)  All direct and indirect costs of procuring, constructing and installing
the Tenant Improvements in the Premises, including, but not limited to, the construction
fee payable to the Contractor for overhead and profit, and the cost of all on-site
supervisory and  

 administrative staff, office, equipment and temporary services rendered by Contractor
in connection with construction of the Tenant Improvements;
 
           (e)  All fees payable to Architect and Landlord's engineering firm if
they are required by Tenant to redesign any portion of the Tenant Improvements following
Tenant's approval of the Final Plans;
 
           (f)  Sewer connection fees (if any);
 
           (g)  All costs of installing an emergency power supply systems in each
of the Buildings, which emergency power supply shall include emergency HVAC for
Tenant's computer rooms;
 
           (h)  All direct and indirect construction costs associated with complying
with Title 24 legislation and ADA compliance for all interior improvements (including
the reconstruction of all restrooms); and
 
           (i)  A construction management fee payable to Landlord equal to three
percent (3%) of the total Tenant Improvement Costs. (Landlord shall either provide,
or cause a third party to provide, construction management services in connection
with the construction of the Tenant Improvements, and the foregoing fee shall be
the sole compensation for such services).
 
      7.   Chance Requests. No revisions to the approved Final Plans shall be
           --------------- made by either Landlord or Tenant unless approved in
writing by both parties. Landlord agrees to make all changes (i) required by any
public agency to conform with governmental regulations, or (ii) requested in writing
by Tenant and approved in writing by Landlord, which approval shall not be unreasonably
withheld. Any costs related to such changes shall be added to the Tenant Improvement
Costs and shall be paid for in accordance with Paragraph 5. The
                                                            ----------- billing
for such additional costs shall be accompanied by evidence of the amounts billed
as is customarily used in the business. Costs related to changes shall include,
without limitation, any architectural, structural engineering, or design fees, and
the Contractor's price for effecting the change. Any change order which may extend
the date of substantial completion of the Tenant Improvements may be disapproved
by Landlord unless Tenant agrees that for all purposes under this Lease, the Tenant
Improvements shall be deemed to have been substantially completed on that date on
which such Tenant Improvements would have been substantially completed without giving
effect to the change order in question.
 
      8.   Early Access.  So long as such entry does not in any way interfere
           ------------                              with or delay Landlord's construction
of the Improvements, Tenant shall have the right to enter the Premises before the
Commencement Date for the purpose of installing cable T.V., telephones, telecommunications
cabling, furniture and other similar items. Such entry shall be subject to all of
the terms and conditions of the Lease, other than the obligation to pay Rent.
 
      9.   Acceptance of Building. Within thirty (30) days after completion of
           ----------------------                      the Tenant Improvements,
Tenant shall conduct a walk-through inspection of the Building with Landlord and
complete a punch-list of items needing additional work. Other than the items specified
in the  

 punch list, if any, by taking possession of the Building, Tenant shall be deemed
to have accepted the Building in good, clean and completed condition and repair,
subject to all applicable laws, codes and ordinances. Any damage to the Building
caused by Tenant's move-in shall be repaired or corrected by Tenant, at its sole
cost and expense, which repair or corrective work shall not be paid for out of any
Tenant Improvements Allowance. Tenant acknowledges that neither Landlord nor Landlord's
agents shall be deemed to have made any representations or warranties as to the
suitability or fitness of the Building for the conduct of Tenant's business or for
any other purpose, nor shall Landlord or Landlord's agents be deemed to have agreed
to undertake any alterations or construct any improvements to the Building except
as expressly provided in the Lease, this Exhibit B, and
                                                                 ---------     
the Build to Suit Option Agreement.  If Tenant fails to submit a punch-list to Landlord
within such 30-day period, it shall be deemed that there are no items needing additional
work or repair.  Contractor shall complete all reasonable punch-list items within
thirty (30) days after the walk-through inspection or as soon as practicable thereafter.
Upon completion of such punch-list items, Tenant shall approve such completed items
in writing to Landlord.  If Tenant fails to approve such items within fourteen (14)
days of completion, such items shall be deemed approved by Tenant.  Landlord shall,
upon Tenant's written request, assign and transfer to Tenant, to the extent reasonably
requested by Tenant and consistent with Landlord's position as the owner of the
Building, Landlord's rights and claims against Contractor arising from Contractor's
warranties (express and implied) with respect to the Building.  Nothing contained
in this Paragraph 10 shall limit, restrict, or terminate any right of Landlord or
Tenant - ------------                                                          
          to make any claim against Contractor based upon the condition of the Building
or any and all of Contractor's warranties (express and implied) with respect to
the Building.

 LANDLORD:                               TENANT:

 MARTIN/CAMPUS ASSOCIATES, L.P.,         AT HOME CORPORATION, a Delaware limited
partnership          a Delaware corporation

 By:  Martin/Redwood Partners,           By:  /s/ Kenneth Goldman
                                              ------------------------
      L.P., a California limited         Its:  Chief Financial Officer
                                              ------------------------
      partnership, its General
      Partner                                 By:  _________________________
                                              Its:  _________________________
      By:  The Martin Group of
           Companies, Inc., a
           California corporation,
           its General Partner
 
           By:  /s/ Cathy Greenwold
                -------------------
           Its:  Vice President
                 -------------- 
 
                                  EXHIBIT C
                                  ---------
 
                              SITE PLAN FOR PROJECT
                              ---------------------
 
           This Exhibit will either be (i) the North Expansion Parcel (see Exhibit
C-1), or (ii) the south campus (see Exhibit C-2), as applicable. 
 
                                  EXHIBIT C
                                  ---------
 
                             [SITE PLAN FOR PROJECT]
                             ----------------------- 
 
                                    EXHIBIT D
                                    ---------
 
                          COMMENCEMENT DATE MEMORANDUM
                          ----------------------------

 LANDLORD:      Martin/Campus Associates, L.P.

 TENANT:        ______________________________

 LEASE DATE:    ______________________________

 PREMISES:      ______________________________

 Pursuant to Paragraph 4.A. of the above referenced Lease, the
             --------------                                    commencement date
is hereby established as __________________ for ____________________, Redwood City,
CA 94063.  The Commencement Date as defined in Paragraph 4.A. shall be ___________________.
    --------------                              
 
                                     TENANT:

 Dated: _________________      AT HOME CORPORATION,
                               a Delaware corporation
 
                                    By:   ______________________________
                                    Its:  ______________________________
 
                                    By:   ______________________________
                                    Its:  ______________________________
 
                                    LANDLORD:

 Dated: _________________      MARTIN/CAMPUS ASSOCIATES, L.P.,
                               a Delaware limited partnership
 
                               By:   Martin/Redwood Partners,
                                     L.P., a California limited
                                     partnership, its General
                                     Partner
 
                                     By:  The Martin Group of
                                          Companies, Inc., a
                                          California corporation,
                                          its General Partner
 
                                          By:  ____________________
                                          Its: ____________________ 
 
                                  EXHIBIT E
                                  ---------
 
             SUBORDINATION, NON-DISTURBANCE AND ATTORNMENT AGREEMENT
             ------------------------------------------------------- 
 
                                    EXHIBIT F
                                    ---------
 
                      STANDARD TERMS FOR OPTION TO PURCHASE
                      -------------------------------------
 
      This Exhibit F sets forth certain standard terms that shall be applicable
           ---------                                                 to the purchase
of the Building pursuant Paragraph 38 of the Lease. This Exhibit
                                          ------------                shall be deemed
a part of the Lease to which it is attached. Capitalized terms which are used herein
and defined in the Lease shall have the meanings given in the Lease.
 
      1.   Sale and Purchase; Title Company.
           -------------------------------- 
 
           1.1  General.  In the event Tenant acquires the Building, (the "Option
                -------                                                    ------
Property"), Landlord shall sell to Tenant, and Tenant shall purchase from - --------
                                                                 Landlord, all of
the "Property" (as defined below).
 
           1.2  The Property.  As used in this Agreement, the term "Property"
                ------------                                                  includes
the Option Property and all of the items referred to in Paragraphs
                                                                  ---------- 1.2.1
through 1.2.4. - -----         ----- 
 
                1.2.1.  Personal Property.  All of Landlord's right, title and
                        -----------------                                      interest
in and to any and all personal property located at the Option Property which is
owned by Landlord and which is used in the operation and maintenance of the Option
Property (the "Personal Property").
                           -----------------   
 
                1.2.2.  Rights and Privileges. All of Landlord's right, title and
                        --------------------- interest, if any, in and to all rights,
privileges, tenements, hereditaments, rights-of-way, easements, appurtenances, mineral
rights, development rights, air rights and riparian or littoral rights belonging
or appertaining to the Option Property.
 
                1.2.3.  Contracts and Leases.  All of Landlord's right, title and
                        --------------------                                   
  interest in and to (i) all service, maintenance, construction, management and
other contracts relating to the Option Property (collectively, "Contracts"), and
                                                                 ---------     
  (ii) all leases, tenancy and occupancy agreements for all or any portion of the
Option Property (collectively, "Leases").
                                 ------   
 
                1.2.4.  Permits and Warranties. All of Landlord's right, title
                        ---------------------- and interest in and to (i) all licenses,
permits and approvals, if any, affecting or pertaining to the Option Property which,
if assignable, are to be assigned to Tenant at the Closing (as defined below), and
(ii) all warranties, if any, affecting or pertaining to the Option Property which,
if assignable, are to be assigned to Tenant at the Closing.
 
           1.3  Title Company.  The purchase and sale of the Property shall be
                -------------                                                  accomplished
through an escrow which Landlord has established or will establish with Chicago
Title Insurance Company, One Kaiser Plaza, Oakland, California (the "Title Company").
 -------------   
 
      2.   Title. Title to the Property shall be conveyed from Landlord to Tenant
           -----                                  by grant deed (the "Deed"), subject
to: (i) liens to secure payment of real estate taxes and assessments not delinquent;
(ii) applicable zoning and use laws, ordinances, rules and regulations of any municipality,
township, county, state or other governmental agency or authority; (iii) all matters


 that would be disclosed by a physical inspection or survey of the Option Property
or that are actually known to Tenant; (iv) any exceptions or matters created by
Tenant, its agents, employees or representatives; (v) all exceptions of record that
were in existence as of the date of the Lease and all CC&Rs recorded by Landlord;
(vi) all Leases and Contracts; and (vii) such other exceptions as Tenant may approve
in writing.
 
      The foregoing exceptions to title are referred to collectively as the "Conditions
of Title". Conclusive evidence of delivery of title in accordance  -------------------
                                                         with the foregoing shall
be the willingness of Title Company to issue to Tenant, upon payment of its regularly
scheduled premium, its CLTA owner's policy of title insurance, in the amount of
the Purchase Price, showing title to the Option Property vested of record in Tenant,
subject only to the Conditions of Title (and the standard printed exceptions and
conditions in the policy of title insurance).  If Landlord for any reason is unable
to deliver title to the Property subject only to the Conditions of Title, then Tenant's
sole remedy shall be to terminate this Agreement and receive a return of any Deposit,
and neither Landlord nor Tenant shall thereafter have any further rights or obligations
under this Agreement, except Tenant's obligation to perform the Continuing Obligations
(as defined below).  Tenant shall have no right to commence any action for damages,
specific performance or other relief as a result of Landlord's inability to deliver
title to the Property subject only to the Conditions of Title; provided, however,
that if Landlord intentionally fails to consummate the conveyance of the Option
Property to Tenant in accordance with the terms of the Lease, then Tenant shall
have the right to commence any actions for damages, specific performance or other
relief as a result of Landlord's intentional breach.
 
      3.   Damage, Destruction or Taking.  If at any time prior to the Closing,
           ----------------------------- Landlord determines that the Option Property
has been destroyed or damaged by earthquake, flood or other casualty and that such
damage will require more than One Million Dollars ($1,000,000.00) to repair (a "Casualty"),
or if a proceeding
                                                   -------- is instituted for the
taking of all or any material portion of the Option Property under the power of
eminent domain (a "Taking"), then Tenant shall have
                                                ------ the right by giving written
notice to Landlord and Title Company within fifteen (15) days after the date of
receipt of written notice of any such Casualty or Taking, either to: (i) consummate
the purchase of the Property in accordance with the Lease, in which event Landlord
shall assign to Tenant at the Closing (A) any insurance proceeds payable to Landlord
on account of such Casualty, or (B) any award payable to Landlord by reason of the
Taking, as the case may be; or (ii) terminate Landlord's obligations under Paragraph
38 of the Lease and
                                                ------------ this Exhibit F, effective
as of the date such notice of termination is given. If
      --------- Tenant fails to give such notice within such 15-day period, then
Tenant shall be deemed to have elected to terminate Landlord's obligations under
Paragraph 38 of
                                                                  ------------ the
Lease and this Exhibit F, pursuant to this Paragraph 3. The Closing Date
                    ---------                   ----------- shall be deferred, if
necessary, to permit Tenant to have the 15-day period following receipt of notice
of a Casualty or a Taking to make the election specified hereinabove. If Tenant
terminates Landlord's obligations under Paragraph 38 of the Lease and this Exhibit
F, pursuant to this Paragraph 3, then - ------------                       ---------
                  ----------- any Deposit shall be returned to Tenant, and neither
Landlord nor Tenant shall have any further obligations under Paragraph 38 of the
Lease or this Exhibit F.
                                    ------------                      ---------
Nothing herein shall be deemed to constitute an obligation on the part of Landlord
to carry or maintain any insurance of any kind whatsoever pertaining to the Property.
 
      4.   Landlord's Disclaimer; Release and Indemnification of Landlord.
           --------------------------------------------------------------- 
 
           4.1  Landlord's Disclaimer.  Tenant acknowledges and agrees that the
                ---------------------                                          
sale of the Property to Tenant is made without any warranty or representation of
any kind by Landlord, either express or implied, with respect to any aspect, portion
or component of the Property, including: (i) the physical condition, nature or quality
of the Property, including the quality of the soils on and under the Property and
the quality of the labor and materials included in any buildings or other improvements,
fixtures, equipment or personal property comprising a portion of the Property; (ii)
the fitness of the Property for any particular purpose; (iii) the presence or suspected
presence of hazardous materials on, in, under or about the Property (including the
soils and groundwater on and under the Property); or (iv) existing or proposed governmental
laws or regulations applicable to the Property, or the further development or change
in use thereof, including environmental laws and laws or regulations dealing with
zoning or land use.  Tenant further agrees and acknowledges that, as of the Closing,
Tenant shall have made such feasibility studies, investigations, environmental studies,
engineering studies, inquiries of governmental officials, and all other inquiries
and investigations, which Tenant shall deem necessary to satisfy itself as to the
condition, nature and quality of the Property and as to the suitability of the Property
for Tenant's purposes. Tenant further agrees and acknowledges that, in purchasing
the Property, Tenant shall rely entirely on its own investigation, examination and
inspection of the Property, and not upon any representation or warranty of Landlord,
or any agent or representative of Landlord.  Tenant further agrees and acknowledges
that Tenant has leased and occupied the Option Property prior to the Closing, by
reason of such tenancy, possession and occupancy, Tenant is fully aware of the condition
of the Option Property.  THEREFORE, TENANT AGREES THAT, IN CONSUMMATING THE PURCHASE
OF THE PROPERTY PURSUANT TO THIS LEASE, TENANT SHALL ACQUIRE THE PROPERTY IN ITS
THEN CONDITION, "AS IS, WHERE IS" AND WITH ALL FAULTS, AND SOLELY IN RELIANCE ON
TENANT'S OWN INVESTIGATION, EXAMINATION, INSPECTION, ANALYSIS AND EVALUATION OF
THE PROPERTY.  The agreements and acknowledgments contained in this Paragraph 4.1
constitute a
                                                  -------------              conclusive
admission that Tenant, as a sophisticated, knowledgeable investor in real property,
shall acquire the Property solely upon its own judgment as to any matter germane
to the Property or to Tenant's contemplated use of the Property, and not upon any
statement, representation or warranty by Landlord, or any agent or representative
of Landlord, which is not expressly set forth in this Agreement.  At the Closing,
upon the request of Landlord, Tenant shall execute and deliver to Landlord a certificate
of Tenant reaffirming the foregoing.
 
           4.2  Tenant's Release of Landlord.  Tenant hereby waives, releases and
                ----------------------------                                   
  forever discharges Landlord and its officers, directors, employees and agents
from any and all claims, actions, causes of action, demands, liabilities, damages,
costs, expenses or compensation whatsoever, whether direct or indirect, known or
unknown, foreseeable or unforeseeable, which Tenant may have at the Closing or which
may arise in the future on account of or in any way arising out of or connected
with the Property, including: (i) the physical condition, nature or quality of the
Property (including the soils and groundwater on and under the Option Property);
(ii) the presence or release in, under, on or about the Property (including the
soils and groundwater on and under the Option Property) of any hazardous materials;
and (iii) the ownership, management or operation of the Property, but excluding
claims to the extent based on Landlord's fraud or intentional misrepresentation.
 At the Closing, upon the request of Landlord, Tenant shall deliver to Landlord
a certificate of Tenant reaffirming the foregoing. Tenant hereby  

 waives the protection of California Civil Code Paragraph 1542, which reads as follows:
 
           "A general release does not extend to claims which the
           creditor does not know or suspect to exist in his favor at
           the time of executing the release, which if known by him
           must have materially affected his settlement with the
           debtor."

 Tenant's Initials: /s/ K. A. G
           -----------
 
           4.3  Tenant's Indemnification of Landlord.  Tenant shall indemnify,
                ------------------------------------                           defend,
protect and hold Landlord harmless from and against any and all claims, actions,
causes of action, demands, liabilities, damages, costs and expenses (including attorneys'
fees), whether direct or indirect, known or unknown, foreseeable or unforeseeable,
which may be asserted against or suffered by Landlord at any time after the Closing
on account of or in any way arising out of or connected with the Property, including:
(i) the physical condition, nature or quality of the Property (including the soils
and groundwater on and under the Option Property); (ii) the presence or release
in, under, on or about the Property (including the soils and groundwater on and
under the Option Property) of any hazardous materials; and (iii) the ownership,
management or operation of the Property, including any claim or demand by any tenant
for the refund or return of any security deposit or other deposit, but excluding
claims to the extent based on Landlord's fraud or intentional misrepresentation.
 At the Closing, upon the request of Landlord, Tenant shall deliver to Landlord
a certificate reaffirming the foregoing.
 
           4.4  Flood Hazard Zone.  Tenant acknowledges that if the Option
                -----------------                                          Property
is located in an area which the Secretary of HUD has found to have special flood
hazards, then pursuant to the National Flood Insurance Program, Tenant will be required
to purchase flood insurance in order to obtain any loan secured by the Option Property
from any federally regulated financial institution or a loan insured or guaranteed
by an agency of the United States government. Tenant shall have sole responsibility
to determine whether the Option Property is located in an area which is subject
to the National Flood Insurance Program.
 
           4.5  Inspections.  Subject to obtaining Landlord's prior written
                -----------                                                 consent,
which shall not be unreasonably withheld or delayed, Tenant shall have the right
to conduct such inspections, investigations, borings, samplings and other tests
of the Property that Tenant deems to be useful or necessary for the conduct of Tenant's
due diligence in connection with the acquisition of the Property.  Upon request
by Tenant, Landlord shall make available to Tenant for inspection all material documents
and reports in Landlord's possession relating to the condition of the Property.
 Tenant shall indemnify, defend, protect and hold Landlord harmless from and against
any and all loss, cost, damage, injury, claim (including claims of lien for work
or labor performed or materials or supplies furnished), liability or expense (including
attorneys' fees) as a result of, arising out of, or in any way connected with the
exercise of Tenant's (or its agents', contractors', employees' or authorized representatives')
inspection rights pursuant to this Paragraph 4.5 or the performance of Tenant's
due diligence. Tenant shall promptly repair any damage to the Property caused by
its due diligence. 
 
      5.   Closing.
           ------- 
 
           5.1.  Closing.  The transaction contemplated by this Exhibit F shall
                 -------                                        ---------      
be consummated through escrow at the office of Title Company on the date described
in Paragraph 5.1.1 below, or on such other date as shall be mutually
              ---------------                                                  
agreed upon by Landlord and Tenant (each, a "Closing Date").  For purposes of
                                              ------------                     this
Exhibit F. the term "Closing" shall mean the consummation of the sale and
                           -------                                             
conveyance of the Property to Tenant as evidenced by recordation of the Deed (as
defined below).
 
                5.1.1.  Closing Date.  The Closing Date shall be no later than
                        ------------                                           the
date specified in the Agreed Terms.
 
           5.2.  Landlord's Delivery Into Escrow.  Landlord shall deliver the
                 -------------------------------                              following
items into escrow:
 
                5.2.1.  Deed.  The Deed, duly executed and acknowledged by
                        ---- Landlord, except that the amount of any transfer tax
shall not be shown on the Deed, but shall be set forth on a separate affidavit or
instrument which, after recordation of the Deed, shall be attached thereto so that
the amount of such transfer tax shall not be of record.
 
                5.2.2.  Other Documents. Such other documents or instruments as
                        --------------- may be reasonably required to consummate
this transaction in accordance with the terms and conditions herein contained, such
as appropriate escrow instructions to Title Company.
 
           5.3.  Tenant's Delivery Into Escrow.  Tenant shall deliver the
                 -----------------------------                            following
items into escrow:
 
                5.3.1.  Cash.  Immediately available funds in the following
                        ---- amounts: (i) the balance of the Purchase Price, less
the amount of the Deposit; (ii) such amount, if any, as is necessary for Tenant
to pay Tenant's share of the closing costs and prorations specified in Paragraphs
5.5 and 5.6; and (iii)
                                               --------------     --- any other
amounts required to close escrow in accordance with the terms of this Exhibit F.
- --------- 
 
                5.3.2.  Other Documents. Such other documents and instruments as
                        --------------- may be reasonably required in order to consummate
this transaction in accordance with the terms and conditions of this Exhibit F and
the Lease, such as
                                       ---------                        appropriate
escrow instructions to Title Company.
 
                5.3.3.  Evidence of Authorization. Such evidence as shall
                        ------------------------- reasonably establish that Tenant's
performance of its obligations under the Lease and this Exhibit F have been duly
authorized and that the person or
                --------- persons executing all documents on behalf of Tenant have
been duly authorized and empowered to do so.
 
           5.4. Landlord's and Tenant's Joint Delivery Into Escrow.  Landlord
                --------------------------------------------------            and
Tenant jointly shall deliver the following items into escrow: 
 
                5.4.1.  Assignment and Assumption Agreements. A document by which
                        ------------------------------------ Landlord assigns to
Tenant, and Tenant assumes, the Leases, Contracts, permits and warranties which
will survive the Closing.
 
                5.4.2.  Other Documents. Such other documents and instruments as
                        --------------- may be reasonably required to consummate
this transaction in accordance with the terms and conditions of this Agreement.
 
           5.5.  Closing Prorations.  At the Closing, all items of income and
                 ------------------                                           expense
of the Property shall be prorated as provided in this Paragraph 5.5 on
                                                               -------------   
the basis of a 360-day year, actual days elapsed for the month in which the Closing
occurs, as of midnight on the day immediately preceding the Closing Date. Except
as provided in this Paragraph 5.5, income and expenses attributable
                                  -------------                                
  to the period prior to the Closing Date shall be for the account of Landlord,
and income and expenses attributable to the period on and after the Closing Date
shall be for the account of Tenant. Property taxes and assessments shall be prorated
through escrow, and all other items of income and expense shall be prorated outside
of escrow on the Closing Date by the parties. Without limiting the generality of
the foregoing, the following items shall be prorated through escrow as described
above:
 
                (a)  Current rents collected by Landlord under the Leases. With
respect to any rent receivables carried by Landlord under the Leases as of the Closing,
Tenant shall pay Landlord full value in immediately available funds at the Closing
and Landlord shall execute and deliver to Tenant at the Closing an assignment of
all of Landlord's right, title and interest with respect thereto.
 
                (b)  Amounts paid or payable in respect of the Contracts which Tenant
assumes at the Closing.
 
           5.6.  Closing Costs.  Landlord shall pay the following closing costs:
                 -------------                                                 
 (i) all fees and costs for releasing all encumbrances, liens and security interests
of record which are not Conditions of Title; and (ii) county documentary or other
transfer taxes payable upon recordation of the Deed. Tenant shall pay the following
closing costs: (a) the premium for Tenant's policy of title insurance; (b) any and
all costs, fees, title insurance premiums and other charges payable in connection
with any financing obtained by Tenant to acquire the Property, including all escrow
fees relating to the funding and/or recordation of such financing; and (c) all escrow
fees. Each party shall pay one-half of any escrow cancellation fee charged by Title
Company in connection with the purchase and sale of the Property in accordance with
this Exhibit F.
                                                                    ---------  
All other closing costs shall be paid by the parties in accordance with the custom
then prevailing in San Mateo County.
 
           5.7.  Security Deposits.  With respect to all Leases which are in
                 -----------------                                           effect
at the Closing, Landlord shall give Tenant at the Closing, through Escrow, a credit
in the amount of all security deposits and other deposits then held by Landlord
under such Leases.
 
           5.8.  Possession.  Subject to the rights of tenants under the Leases,
                 ----------                                                    
 Landlord shall deliver exclusive possession of the Property to Tenant at the Closing.

 
           5.9.  Closing Procedure.  Title Company shall close escrow when it is
                 -----------------                                             
 in a position to: (i) pay to Landlord, in immediately available funds, the amount
of the Purchase Price, as such amount may be increased or decreased as a result
of the allocation of the closing costs and prorations as specified in Paragraphs
5.5 and 5.6 and Landlord's obligations with respect to security - --------------
    ---                                                     deposits as specified
in Paragraph 5.7; and (ii) issue to Tenant the policy of
                          -------------                                        
title insurance referred to in Paragraph 2.
                                ----------- 
 
           5.10.  Escrow.  Within five (5) days after Landlord and Tenant have
                  ------                                                       agreed
upon the Agreed Terms, Tenant and Landlord shall deposit an executed counterpart
of this Exhibit F with the Title Company and this Exhibit F shall
                     ---------                                 ---------       serve
as instructions to the Title Company for consummation of the purchase and sale contemplated
hereby. Landlord and Tenant shall execute such supplemental escrow instructions
as may be appropriate to enable the Title Company to comply with the terms of this
Exhibit F. provided such supplemental escrow instructions
                        ---------                                              
  are not in conflict with this Exhibit F. In the event of any conflict between
                               ---------                                       the
provisions of this Exhibit F and any supplementary escrow instructions
                        ---------                                           signed
by Tenant and Landlord, the terms of this Exhibit F shall control.
                                                  ---------               
 
           5.11.  Compliance.  The Title Company shall comply with all applicable
                  ----------                                                   
  federal, state and local reporting and withholding requirements relating to the
close of the transactions contemplated herein.  Without limiting the generality
of the foregoing, to the extent the transactions contemplated by this Exhibit F
                                                                       ---------
involve a real estate transaction within the purview of Section 6045 of the Internal
Revenue Code of 1986, as amended (the "Internal Revenue Code"), Title
                                                 ---------------------         
Company shall have sole responsibility to comply with the requirements of Section
6045 of the Internal Revenue Code (and any similar requirements imposed by state
or local law).  For purposes of this Paragraph 5.11, Landlord's tax
                                               --------------                 identification
number is 94-3236971.  Title Company shall hold Tenant, Landlord and their counsel
free and harmless from and against any and all liability, claims, demands, damages
and costs, including reasonable attorney's fees and other litigation expenses, arising
or resulting from the failure or refusal of Title Company to comply with such reporting
requirements.
 
      6.   Survival of Provisions.  Notwithstanding any other provision of this
           ----------------------                                              
Exhibit F to the contrary, each representation, warranty, covenant or agreement
contained in this Exhibit F (including Tenant's obligations pursuant to
                   ---------                                             Paragraph
4.3) shall survive and be binding and enforceable following the - -------------
                                                            Closing and shall not
be deemed to be merged into, or waived by delivery or recordation of, the Deed or
any other instruments delivered at the Closing.
 
      7.   Exchange.  At the option of either party, such party may elect to
           --------                                                          consummate
the transaction hereunder in whole or in part as a like-kind exchange pursuant to
Section 1031 of the Internal Revenue Code of 1986, as amended.  If either party
(the "Exchanging Party") so elects, the other party (the
                    ----------------                                   "Cooperating
Party") shall cooperate with the Exchanging Party, executing such - ------------------
                                                            documents and taking
such action as may be reasonably necessary in order to effectuate this transaction
as a like-kind exchange; provided, however, that (i) the Cooperating Party's cooperation
hereunder shall be without cost, expense or liability to the Cooperating Party of
any kind or character, including, without limitation, any attorneys' fees, costs
or expense incurred in connection with the review or preparation of documentation
in order to effectuate such like-kind exchange, and the Cooperating Party shall
have no obligation to take title to any real property;  

 (ii) the Exchanging Party shall assume all risks in connection with the designation,
selection and setting of terms of the purchase or sale of any exchange property;
(iii) the Exchanging Party shall bear all costs and expenses in connection with
any such exchange transaction in excess of the costs and expenses which would have
otherwise been incurred in acquiring or selling the Property by means of a straight
purchase, so that the net effect to the Cooperating Party shall be identical to
that which would have resulted had this Exhibit F closed on a purchase and sale;
(iv) any documents to effectuate such - ---------                              
                                  exchange transaction are consistent with the terms
and conditions contained in this Exhibit F; and (v) the Exchanging Party shall indemnify,
defend and hold
      ---------                                                                the
Cooperating Party harmless from any and all claims, demands, penalties, loss, causes
of action, suits, risks, liability, costs or expenses of any kind or nature (including,
without limitation, reasonable attorneys' fees) which the Cooperating Party may
incur or sustain, directly or indirectly, related to or in connection with, or arising
out of, the consummation of this transaction as a like-kind exchange as contemplated
hereunder.
 
      8.   Deposit.  Notwithstanding anything to the contrary set forth in the
           -------                                                             Agreed
Terms or this Exhibit F, within one (1) day after Landlord and Tenant
                      ---------                                               reach
agreement on the Agreed Terms for Tenant's purchase of the Property from Landlord,
Tenant shall deliver to Title Company a cashier's check in the amount of five percent
(5%) of the Purchase Price (the "Deposit"), as an earnest money
                                                  -------                      
 deposit on account of the Purchase Price.  Title Company shall deposit the Deposit
in an interest-bearing account, and the term "Deposit" as used in this
                                                       -------                 
Exhibit F shall include any interest earned thereon. - ---------               
                           
 
      9.   Liquidated Damages.  TENANT ACKNOWLEDGES THAT THE CLOSING OF THE SALE
           ------------------                                                  
 OF THE PROPERTY TO TENANT, ON THE TERMS AND CONDITIONS AND WITHIN THE TIME PERIOD
SET FORTH IN THIS EXHIBIT F AND THE LEASE, IS MATERIAL TO LANDLORD.
                          ---------                                          TENANT
ALSO ACKNOWLEDGES THAT SUBSTANTIAL DAMAGES WILL BE SUFFERED BY LANDLORD IF SUCH
TRANSACTION IS NOT SO CONSUMMATED DUE TO TENANT'S DEFAULT. TENANT FURTHER ACKNOWLEDGES
THAT, AS OF THE DATE THE PARTIES REACH AGREEMENT ON THE AGREED TERMS, LANDLORD'S
DAMAGES WOULD BE EXTREMELY DIFFICULT OR IMPOSSIBLE TO COMPUTE IN LIGHT OF THE UNPREDICTABLE
STATE OF THE ECONOMY AND OF GOVERNMENTAL REGULATIONS, THE FLUCTUATING MARKET FOR
REAL ESTATE AND REAL ESTATE LOANS OF ALL TYPES, AND OTHER FACTORS WHICH DIRECTLY
AFFECT THE VALUE AND MARKETABILITY OF THE PROPERTY.  IN LIGHT OF THE FOREGOING AND
ALL OF THE OTHER FACTS AND CIRCUMSTANCES SURROUNDING THIS TRANSACTION, AND FOLLOWING
NEGOTIATIONS BETWEEN THE PARTIES, TENANT AND LANDLORD AGREE THAT THE AMOUNT OF THE
DEPOSIT REPRESENTS A REASONABLE ESTIMATE OF THE DAMAGES WHICH LANDLORD WOULD SUFFER
BY REASON OF TENANT'S DEFAULT HEREUNDER.  ACCORDINGLY, TENANT AND LANDLORD HEREBY
AGREE THAT, IN THE EVENT OF SUCH DEFAULT BY TENANT, LANDLORD MAY TERMINATE ITS OBLIGATIONS
UNDER PARAGRAPH 38 OF THE LEASE AND THIS EXHIBIT F BY GIVING NOTICE TO TENANT.
       ------------                       ---------                            
 IN THE EVENT OF SUCH TERMINATION, LANDLORD SHALL RETAIN THE DEPOSIT AS LIQUIDATED
DAMAGES IN LIEU OF ANY OTHER CLAIM LANDLORD MAY HAVE AT LAW OR IN EQUITY (INCLUDING,
WITHOUT LIMITATION, SPECIFIC PERFORMANCE) ARISING  

 BY REASON OF TENANT'S FAILURE TO PURCHASE THE PROPERTY PURSUANT TO THIS EXHIBIT
                                                                         -------
F. LANDLORD'S RETENTION OF THE DEPOSIT PURSUANT TO THIS PARAGRAPH 9 SHALL IN NO
- --                                                      -----------

 WAY LIMIT ANY OF LANDLORD'S RIGHTS OR REMEDIES UNDER THE LEASE WITH RESPECT TO
ANY DEFAULT BY TENANT UNDER THE LEASE. THE PARTIES HAVE INITIALED THIS PARAGRAPH
                                                                        ---------
9 TO ESTABLISH THEIR INTENT SO TO LIQUIDATE DAMAGES. NOTWITHSTANDING THE - - FOREGOING,
NOTHING CONTAINED IN THIS PARAGRAPH 9 SHALL BE DEEMED TO LIMIT: (i)
                                      -----------                              
TENANT'S OBLIGATIONS UNDER THE LEASE; OR (ii) TENANT'S INDEMNIFICATION OBLIGATIONS
CONTAINED IN THIS EXHIBIT F.
                               --------- 

 Landlord's                    Tenant's Initials: _____               Initials:
 /s/ K.A.G.
                                          ----------
 
                                     TENANT:

 Dated: September 24, 1997     AT HOME CORPORATION,
                               a Delaware corporation
 
                                    By:  /s/ Kenneth Goldman
                                         -----------------------
                                    Its: Chief Financial Officer
                                         -----------------------
 
                                    By:  _______________________ 
                                    Its: _______________________
 
                                    LANDLORD:

 Dated:  September 29, 1997    MARTIN/CAMPUS ASSOCIATES, L.P.,
                               a Delaware limited partnership
 
									By:   Martin/Redwood Partners,
										  L.P., a California limited
										  partnership, its General
										  Partner
									
									By:   The Martin Group of
									      Companies, Inc., a
									      California corporation,
									      its General Partner
									
									By:  /s/ Cathy Greenwold
										-------------------
									Its: Vice President
										-------------------