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                                                                    EXHIBIT 10.5
                                    SUBLEASE

         This Sublease is entered into this 26th day of March, 1997, between
Carollo Engineers, an Arizona partnership ("Sublessor") and ParcPlace Digitalk,
a Delaware corporation ("Sublessee").

         Sublessor is the Tenant under a Lease from Spieker Properties,
successor-in-interest to VFT Real Estate Corp. IV, a Delaware corporation,
Landlord, dated March 3, 1994 (the "Lease"). The lease covers approximately
2,862 rentable sq. ft. in the building located at 5100 SW Macadam Avenue, Suite
350, Portland Oregon. A complete copy of the Lease is attached hereto as
Exhibit A.

         Sublessee wishes to sublease from Sublessor, all of the premises
covered by the Lease.

         NOW THEREFORE, Sublessor hereby subleases the premises described in the
attached Exhibit B (the "Premises"), an area of approximately 2,862 rentable sq.
ft. and Sublessee agrees to sublease the Premises from Sublessor on the
following terms:

1.    Term                 The term of this Sublease shall commence on April 15,
                           1997, and shall continue through and including June
                           29, 2000.

2.    Rent                 Sublessee shall pay to Sublessor base rent in the sum
                           of 53,458.25 per month from April 15, 1997 through
                           June 30, 1997, and $3,577.50 per month from July 1,
                           1997 through June 29, 2000 on the first day of each
                           month of the lease term. Base rent shall be escalated
                           at the same time and in the same amount per square
                           foot as the rent paid by Sublessor to the Landlord
                           under Sections 19.1 & 19.4, Excavation Provisions, in
                           the Maters Lease dated march 4, 1994. Sublessor shall
                           pay to the Landlord under the Lease all rent and
                           other charges required to be paid by Sublessor under
                           the Lease.

3.    Sublessee
      Consideration        Sublessee shall pay the sum of $0 as sublease
                           consideration. Sublessor may apply the sublease
                           consideration to pay the cost of performing any
                           obligation which Sublessee fails to perform within
                           the time required by this Sublease, but such
                           application by Sublessor shall not be the exclusive
                           remedy for Sublessee's default. If the sublease
                           consideration is applied by Sublessor, Sublessee
                           shall on demand pay the sum necessary to replenish
                           the sublease consideration to its original amount. To
                           the extent not applied by Sublessor to cure defaults
                           by Sublessee, the sublease consideration shall be
                           applied against the rent payable for the last month
                           of the term. The sublease consideration shall not be
                           refundable.


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4.    Obligations of
      Sublessee            Sublessee shall perform all of the obligations of
                           Tenant under the Lease (except the obligation to pay
                           rent and other obligations inconsistent with this
                           Sublease) as if Sublessee were the Tenant under the
                           Lease and Sublessor was the Landlord under the Lease.
                           The terms of the Lease are hereby expressly
                           incorporated as part of this Sublease. In the event
                           Sublessee fails to comply with such terms, or the
                           terms of this Sublease, Sublessor shall be entitled
                           to all of the remedies granted to Landlord in the
                           Lease, together with any other rights Sublessor might
                           otherwise have. All provisions in the Lease dealing
                           with indemnity and liability shall be applicable as
                           between Sublessor and Sublessee and Sublessees and
                           the Landlord under the Lease. Sublessee shall name
                           both Sublessor and the Landlord and Landlord's
                           managing agent under the Lease as named insured in
                           the insurance policies it is required to obtain
                           hereunder.

5.    Representations
      of Sublessor         Sublessor represents and warrants that the Lease is
                           in good standing and that Sublessor has, to the best
                           of its knowledge, complied with all of its
                           obligations thereunder through the date hereof.
                           Sublessor shall make all rental and other payments
                           required by the Lease.

6.    Condition of
      Premises             Unless otherwise expressly provided herein, the
                           Premises are leased as in the condition now existing
                           with no additional work to be performed by Sublessor
                           or Landlord.

7.    Notices              With respect to notices between Sublessor and
                           Sublessee, the addresses for notice shall be the
                           addresses stated in this Sublease.

8.    Waiver of
      Subrogation          Neither Sublessor, Sublessee nor the Landlord under
                           the Lease (nor Landlord's managing agent) shall have
                           any claim against the other for any loss or damage of
                           a type which is coverable by fire and extended
                           coverage insurance, including water damage or
                           sprinkler leakage, regardless of negligence.

9.    Sublessee
      Improvements         Sublessee improvements to space shall be at the sole
                           cost and responsibility of Sublessee. All
                           improvements to said space shall be approved by
                           Sublessor and Landlord.

10.   Option to
      Terminate            As per paragraph 23 of the Addendum to the Master
                           Lease dated March 3, 1994, Carollo Engineers agrees,
                           so long as Sublessee is not in default, not to
                           terminate this lease through June 29, 2000.

11.   Additional
      Provisions           This Sublease incorporates the terms and conditions
                           contained in the following Exhibits:


      Exhibit A - The Lease
      Exhibit B - Description of the Premises


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         IN WITNESS WHEREOF, the parties have executed this Sublease as of the
day and year first written above.


SUBLESSOR:                                          By:_________________________
Carollo Engineers, an Arizona                             Gary Deis, Partner
partnership

Address for notices:
c/o Bob Eimsead
Carollo Engineers
5100 SW Masadarm Avenue, Suite 440
Portland, OR  97201

SUBLESSEE:                                        By:___________________________
ParcPlace Digitalk, Inc., a Delaware
corporation                                       Title:________________________

Address for notices:
999 E. Arguas
Sunnyvale, CA  94086


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