Exhibit 10.1

                           ZARLINK SEMICONDUCTOR INC.
                          (formerly Mitel Corporation)

                                      -and-

                          METASOLV SOFTWARE CANADA INC.

- --------------------------------------------------------------------------------

                                 S U B L E A S E

- --------------------------------------------------------------------------------

                          Osler, Hoskin & Harcourt LLP



                                TABLE OF CONTENTS

                                                                            Page

1.  Capitalized Terms .....................................................    2


2.  Definitions ...........................................................    2


3.  Demise and Subterm ....................................................    2


4.  Subtenant's Right to Extend the Subterm ...............................    2


5.  Early Access ..........................................................    3


6.  Basic Rent ............................................................    4


7.  Additional Rent and Escalation Payments ...............................    4


8.  Rights of First Refusal ...............................................    5


9.  Rights of Expansion ...................................................    5


10. Payments ..............................................................    5


11. Subtenant's Covenants .................................................    5


12. Subtenant's Breach ....................................................    7


13. Sublandlord's Covenants ...............................................    7


14. Use and Access ........................................................   10


15. Parking ...............................................................   10


16. Insurance .............................................................   10


17. Subtenant's Assigning, Subletting, Etc. ...............................   10


18. Other Terms of Head Lease Incorporated ................................   11


19. Exercise of Rights ....................................................   11


20. Notices and Consents, Etc. ............................................   11


21. Successors and Assigns ................................................   12


22. Further Assurances ....................................................   12


23. Governing Law .........................................................   13
    SCHEDULE A HEAD LEASE .................................................    1
    SCHEDULE B FLOOR PLAN SHOWING SUBLET PREMISES SHADED ..................    1
    schedule c form of subtenant letter of credit .........................    1



THIS SUBLEASE is made as of this 4th day of June, 2002


Pursuant to the Short Forms of Leases Act of Ontario


BETWEEN:

                           Zarlink Semiconductor Inc.,
                           (formerly Mitel Corporation, the "Sublandlord")


                           - and -


                           MetaSolv Software Canada Inc.

                           (the "Subtenant").


RECITALS:

A.       By a lease (the "Head Lease") made as of March 27, 2001, a copy of
         which is attached hereto as Schedule A, Mitel Research Park Corporation
         (the "Head Landlord")leased to Mitel Corporation (a predecessor company
         of the Sublandlord), for a term commencing on March 27, 2001 and
         terminating on March 26, 2011, upon and subject to the terms of the
         Head Lease, certain office space and laboratory space in the building
         complex municipally known as 400 March Road and 340, 350 and 360 Legget
         Drive, in the City of Ottawa, in the Province of Ontario (the
         "Building"), which premises are more particularly described in the Head
         Lease including, inter alia, those portions of the first and second
         floors of the Building which portions contain approximately 31,358
         square feet and are shown shaded on the floor plans attached hereto as
         Schedule B (the "Sublet Premises).


B.       The Sublet Premises are comprised of approximately 6,000 square feet of
         Rentable Area on the ground floor of 360 Legget Drive and 25,358 square
         feet of Rentable Area on the second floor of 360 Legget Drive. The
         Sublet Premises includes certain office (the "Office Space") and
         certain laboratory space (the "Laboratory Space"), both as shown shaded
         on Schedule B.

C.       Subject to the Head Landlord's consent, the Sublandlord and Subtenant
         have agreed to sublet the Sublet Premises on the terms set forth
         herein.


THEREFORE in consideration of the rents, covenants and agreements hereinafter
set forth and other good and valuable consideration and the sum of $10.00 paid
by each party to each other party, the receipt and sufficiency of which are
hereby acknowledged by each party, the parties covenant and agree as follows:



                                      -2-

1.       Capitalized Terms

Each capitalized term used herein shall have the meaning ascribed to it herein
and if not herein then in the Head Lease.

2.       Definitions

"Business Day" means any day, other than a Saturday or Sunday, on which the
chartered banks in Ottawa, Ontario are open for commercial banking business
during normal banking hours;

"Rent" means Basic Rent and any other monthly payments to be made by the
Subtenant to the Sublandlord hereunder; and


"Rentable Area" means the rentable area of the Sublet Premises as evidenced by a
Certificate of Measurement prepared by the Sublandlord in accordance with the
"Standard Method for Measuring floor Area in Office Buildings" published by the
Buildings Owners and Managers Association ("BOMA") International (An American
National Standard, approved June 7, 1996 by American National Standards
Institute, Inc.)

3.       Demise and Subterm

Subject to the consent of the Head Landlord, the Sublandlord demises and
subleases the Sublet Premises to the Subtenant and the Subtenant subleases the
Sublet Premises from the Sublandlord, for a term (hereinafter called the
"Subterm") commencing on July 1, 2002 (hereinafter called the "Commencement
Date") and terminating on June 30, 2007 upon and subject to the terms of this
Sublease.

4.       Subtenant's Right to Extend the Subterm

Provided that, at the end of the Subterm, the Sublandlord does not require the
Sublet Premises for the purposes of carrying on its business, the Subtenant
shall have the right to extend this Sublease (the "Extension Term") commencing
on the day following the last day of the Subterm and extending until March 25,
2011, subject to the following terms and conditions:

         (a)  the Subtenant's right to extend shall not enure to the benefit of
              or be exercisable by any subtenant of the Subtenant, and shall
              only enure to the benefit of and be exercisable by an assignee of
              the Subtenant if:

              (i)  the assignee is an affiliate (as defined in Section 12.2 of
                   the Head Lease) of the Subtenant in respect of whom the
                   consent of the Sublandlord is not required in order to assign
                   this Sublease, or



                                      -3-

              (ii) at the time the consent of the Sublandlord to the assignment
                   of this Sublease to the assignee is obtained, the Sublandlord
                   also consents to the assignment of such right to extend to
                   the assignee, which consent the Sublandlord agrees shall not
                   be unreasonably or arbitrarily withheld, conditioned or
                   delayed.

         (b)  the Subtenant shall not be entitled to any right of extension if,
              at the time of the giving of the notice of exercise thereof, the
              Subtenant is in material default hereunder and such default is not
              cured within the time permitted by this Sublease, or if prior
              thereto the Subtenant has been in default hereunder on a
              consistent basis and has been given prior written notice of such
              event of default or events of default by the Sublandlord;

         (c)  the Sublandlord shall provide the Subtenant with written notice at
              least 6 months prior to the expiration of the Subterm stating
              whether it requires the use of the Sublet Premises at the end of
              the Subterm for the purpose of carrying on its business (and if
              such is the case then paragraph 13(f) shall apply) and if the
              Sublandlord shall fail to give such notice it shall be deemed not
              to require the Sublet Premises for the purpose of carrying on its
              business;

         (d)  the right of extension shall be exercisable by written notice by
              the Subtenant to the Sublandlord at least 4 months and not more
              than 6 months prior to the expiration of the Subterm;

         (e)  if the Subtenant has properly exercised its right of extension,
              this Sublease shall be extended for the Extension Term on the same
              terms and conditions as are contained in this Sublease
              supplemented as follows: (i) all references to the Subterm shall
              be deemed to include the Extension Term, (ii) the Basic Rent
              during the Extension Term will be as stipulated in subsection (f)
              below, (iii) there shall be no further right to extend and (iv)
              there shall be no Subtenant inducements; and

         (f)  the annual Basic Rent during the Extension Term shall be CDN$20.00
              per square foot of Rentable Area in the Sublet Premises.


5.       Early Access

Immediately upon execution of this Sublease by the Sublandlord and the
Subtenant, but subject to the following conditions precedent:

         (a)  payment by the Subtenant to the Sublandlord of the first monthly
              instalment of Basic Rent (as defined below) and the Security
              Deposit (as defined below); and



                                      -4-

         (b)  the Subtenant obtaining all insurance required under the Head
              Lease and this Sublease,


the Subtenant may access the Sublet Premises without any obligation to pay Rent
until the Commencement Date. If the Head Landlord does not consent to this
Sublease then the first monthly instalment of Basic Rent and the Security
Deposit shall be refunded to the Subtenant.

6.       Basic Rent

The Subtenant covenants to pay as Basic Rent commencing on the Commencement Date
the sum of CDN$18.00 per square foot of Rentable Area per annum in equal monthly
instalments payable in advance on the first day of each and every month during
the Subterm. The Sublandlord, at its expense, prior to the Commencement Date or
as soon as possible thereafter, shall provide a Certificate prepared by a
certified Ontario Land Surveyor (OLS) as to the Rentable Area of the Sublet
Premises. The Subtenant agrees to pay a pro-rated amount of Basic Rent for any
part month during the Subterm. The Subtenant agrees to pay upon execution hereof
the first monthly instalment of Basic Rent and the last monthly instalment of
Basic Rent (the "Security Deposit"). If the Subtenant is not in default under
this Sublease the Security Deposit shall be credited to the Basic Rent payable
for the last month of the Subterm.

7.       Additional Rent and Escalation Payments

         (a)  The Subtenant shall not pay any Additional Rent as defined in the
              Head Lease except as set out herein. Commencing on July 1, 2003
              and during the remainder of the Subterm, the Subtenant agrees to
              pay in equal monthly instalments payable in advance on the first
              day of each and every month (an "Escalation Payment") the amount
              by which the annual Additional Rent payable by the Sublandlord to
              the Landlord under the Head Lease for the Sublet Premises
              increases over and above the amount of annual Additional Rent paid
              by the Sublandlord to the Landlord under the Head Lease for the
              Sublet Premises during the year ending on December 31, 2002 (the
              "Base Year").

         (b)  If the Subtenant exercises its right to extend the Subterm, then
              during such Extension Term, the monthly Escalation Payments shall
              be calculated using a Base Year of 2007.

         (c)  In addition to the Escalation Payments set out above, the
              Subtenant agrees to pay to the Sublandlord on a monthly basis the
              cost of all electrical power consumed in the Laboratory Space as
              charged to the Sublandlord by the Head Landlord and including any
              administrative fees of the Head Landlord.



                                      -5-

8.       Rights of First Refusal

If, at any time and from time to time, the Sublandlord receives a bona fide
third party offer to sublet any space adjoining the Sublet Premises which the
Sublandlord is prepared to accept, the Sublandlord shall first notify the
Subtenant in writing of this fact and of the terms of such offer to sublet such
space. The Subtenant shall then have the right, exercisable by notice in writing
to the Sublandlord within five Business Days after receipt by the Subtenant of
the written notice from the Sublandlord, to sublet such space on the same terms
as those contained in such third party offer. If the Subtenant does not exercise
such right within such period, the Sublandlord shall be free to sublet such
space on the terms set out in such third party offer.

9.       Rights of Expansion

If, at any time and from time to time, space within Phase III of the Leased
Premises becomes available to be sublet, whether adjoining the Sublet Premises
or not, the Sublandlord shall notify the Subtenant in writing of this fact prior
to advertising the availability of such space or seeking or entertaining any
offer to sublet such space. Such notice shall set out the approximate amount of
space available to be sublet. The Subtenant shall then have the right,
exercisable by notice in writing to the Sublandlord within five Business Days
after receipt by the Subtenant of the written notice from the Sublandlord, to
make an offer to the Sublandlord to rent a portion of or all such space on terms
identical to those set out in this Sublease, provided that, if the Subtenant
wishes to sublet only a portion of such space, the remaining portion of such
space shall be of a size which is commercially viable for subletting to a third
party. If such right to expand is not exercised by the Subtenant within such
period, the Sublandlord shall be free to sublet such space on such terms or
substantially such terms to any other person.

10.      Payments

All payments provided for in this Sublease shall be in Canadian currency and
shall be made by the Subtenant to the Sublandlord at its address provided in
section 21 hereof or as the Sublandlord otherwise directs by notice.

11.      Subtenant's Covenants

The Subtenant also covenants and agrees with the Sublandlord:

         (a)  to perform all of the obligations of the Tenant under the Head
              Lease and to be bound by the terms of the Head Lease as such
              obligations and terms relate to the Sublet Premises only, and in
              each case as such obligations and terms may be qualified by
              another provision of this Sublease, and except as to Rent and
              other monetary obligations, the obligations of the Subtenant in
              that respect being limited to the Rent and the other amounts which
              are payable under this Sublease;

         (b)  to perform all of the obligations of the Subtenant under this
              Sublease;



                                      -6-

         (c)  not to do or omit to do any act in or around the Sublet Premises
              which would cause a breach of the Sublandlord's obligations as
              Tenant under the Head Lease;


         (d)  to indemnify and save harmless the Sublandlord against and from
              any and all expenses, costs, damages, suits, actions or
              liabilities ("Costs") arising out of the failure of the Subtenant
              to perform any of its obligations hereunder and from all claims
              and demands of every kind and nature ("Claims") made by any person
              or persons to or against the Sublandlord for all and every manner
              of Costs incurred by or injury or damage to such person or persons
              or his, her or their property, if such Claims arise out of the use
              and occupation of the Sublet Premises, the cafeteria or the
              fitness centre (i.e., Zarfit) by the Subtenant or any other person
              authorized by the Subtenant, and from all Costs incurred in and
              about any such Claim or any action or proceeding brought thereon,
              except to the extent such Costs or Claims arise out of or are
              caused by or attributable to an act or omission of the Sublandlord
              or those for whom it is at law responsible;


         (e)  notwithstanding subsection (a) above:


              (i)   the Sublandlord shall, at its expense, provide all
                    maintenance services (except for janitorial services which
                    shall be provided and paid for by the Subtenant) to the
                    Sublet Premises and shall be responsible, at its sole cost
                    and expense, to repair the roof, structural components,
                    Leasehold Improvements, equipment, heating, cooling,
                    ventilating, air-conditioning, plumbing and other electrical
                    and mechanical installations of and serving the Sublet
                    Premises, in accordance with sections 7.1 and 7.8 of the
                    Head Lease;

              (ii)  the Subtenant shall pay any costs incurred by the
                    Sublandlord as a result of the Subtenant operating the
                    Sublet Premises beyond normal business hours (i.e., 8am to
                    6pm) or operating the Sublet Premises other than as set out
                    in section 14 below;


              (iii) the Sublandlord shall reimburse the Head Landlord for any
                    and all costs incurred by the Head Landlord in completing
                    any Leasehold Improvements, work or repairs requested by the
                    Subtenant whether such charges are passed on to the
                    Sublandlord by the Head Landlord or not;

              (iv)  for the initial Subterm, the Subtenant shall not be
                    obligated, as required under section 2.5 of the Head Lease
                    to remove any Leasehold Improvements, trade fixtures,
                    furniture and equipment or make good, at its expense, any
                    damage caused by removal of its Leasehold Improvements,
                    trade fixtures, furniture and equipment; and


                                      -7-

              (v)   the Subtenant shall not be obligated, as required under
                    section 11.5 of the Head Lease to, at its expense, cause an
                    environmental engineering firm or environmental consultant
                    to conduct a Phase II Environmental Assessment of the Sublet
                    Premises, unless the Subtenant brings onto the Complex any
                    materials or substances of a hazardous nature.

         (f)  to program and maintain, at its sole cost, certain segments of the
              Intrusion Detection/Access Control System to be designated by the
              Sublandlord as such relate to the Sublet Premises; and

         (g)  that it has dealt with no broker, finder, agent or other person in
              connection with the Sublease other than The Staubach Ontario Inc.
              (the "Subtenant Brokers"), and it agrees to indemnify and hold the
              Sublandlord harmless from and against any claims or causes of
              action for a commission or other form of compensation arising from
              this Sublease, whether advanced by the Subtenant Brokers or any
              other person or entity. The provisions of this paragraph shall
              survive the termination of the Head Lease, this Sublease and any
              renewal or extension of either or both of them.

12.      Subtenant's Breach

If the Subtenant fails to perform any of its obligations herein, the Sublandlord
shall have all of the remedies against the Subtenant which the Head Landlord has
under the Head Lease for a breach thereof.

13.      Sublandlord's Covenants

Subject to the due performance by the Subtenant of its obligations herein, the
Sublandlord covenants and agrees with the Subtenant:

         (a)  for quiet enjoyment of the Sublet Premises, and the Sublandlord
              represents and warrants to the Subtenant (and acknowledges that
              the Subtenant, in entering into this Sublease, is relying
              thereon), that the Head Lease is in full force and effect and is
              unamended and the Sublandlord has fulfilled all of its obligations
              to date under the Head Lease and is not in default thereunder;

         (b)  to enforce against the Head Landlord for the benefit of the
              Subtenant, its permitted successors and assigns and other lawful
              occupants of the Sublet Premises the covenants and obligations of
              the Head Landlord under the Head Lease with the intent that the
              benefit of such covenants and obligations shall extend to the
              Sublet Premises and be enjoyed by the Subtenant, its permitted
              successors and assigns and other lawful occupants;



                                      -8-

         (c)  to observe and perform all of the obligations of the Sublandlord
              under this Sublease;

         (d)  to pay all Rent and other amounts payable under the Head Lease and
              to duly observe and perform all of the obligations of the Tenant
              under the Head Lease except to the extent such obligations are to
              be observed and performed by the Subtenant under this Sublease;

         (e)  to immediately notify the Subtenant in writing of any default in
              the payment of Rent by the Sublandlord to the Head Landlord or any
              other default of the Sublandlord under the Head Lease which is not
              or which cannot be remedied in accordance with the terms of the
              Head Lease and which default, may or does result in the Head
              Landlord terminating the Head Lease;

         (f)  Contemporaneously with the delivery of the Head Landlord's consent
              to this Sublease by the Head Landlord, the Sublandlord agrees to
              post an irrevocable standby demand letter of credit from a
              Canadian chartered bank in favour of the Subtenant in the amount
              of CDN$250,000 in the form attached as Schedule C, (the "Subtenant
              Letter of Credit") for the whole of the Subterm. The Subtenant
              Letter of Credit may be for a term of not less than one (1) year
              and shall provide for successive automatic one (1) year
              extensions. If the Subtenant receives notice from the issuing bank
              or otherwise becomes aware that the Subtenant Letter of Credit
              will not be extended in accordance with its terms, the Subtenant
              shall be entitled to immediately draw down the full amount of the
              Subtenant Letter of Credit and hold and apply the amount so drawn
              as provided below in substitution for the Subtenant Letter of
              Credit, and the Sublandlord will not be entitled to any interest
              on the amount so held by the Subtenant. The Subtenant may only
              draw down the Subtenant Letter of Credit if: (i) the Tenant
              defaults in its payment of Rent under the Head Lease and does not
              remedy such default in accordance with the terms of the Head Lease
              and which default results in the Head Landlord terminating the
              Head Lease; (ii) the Head Lease is terminated due to the default
              or insolvency of the Sublandlord or for any other reason except
              condemnation, fire or other casualty; or (iii) the Sublandlord
              notifies the Subtenant that it requires the Sublet Premises at the
              end of the Subterm for the purpose of carrying on its business,
              pursuant to section 5(c) above. Upon receiving from the Landlord
              or Tenant written notice of an event set out in (i) or (ii) above,
              the Subtenant may immediately draw down the entire amount of the
              Subtenant Letter of Credit and may retain the proceeds thereof for
              its sole benefit as compensation for the estimated liquidated
              damages and costs (and not as a penalty) which may be suffered or
              incurred by the Subtenant due to the termination of the Head
              Lease. Upon receiving from the Sublandlord written notice as set
              out in (iii) above, then, not later than thirty (30) days prior to
              the expiry of the Subterm, the Sublandlord will either make a cash
              payment to the Subtenant in the amount of $250,000, or if



                                      -9-

              it shall fail to do so, the Subtenant may immediately draw down
              the entire amount of the Subtenant Letter of Credit, and it may
              retain the cash payment or the proceeds of the Subtenant Letter of
              Credit for its sole benefit as agreed compensation for the
              estimated additional costs which the Subtenant may incur to lease
              premises at another location, relocate its business, and for the
              disruption of its business and consequent loss of profit, whether
              or not any or all of such additional costs or loss are actually
              suffered or incurred. For greater certainty, the Sublandlord
              agrees that the Subtenant Letter of Credit and the Subtenant's
              rights under this paragraph will not be released, discharged or
              affected in any way by the bankruptcy, receivership or insolvency
              of the Sublandlord, by a disclaimer of the Head Lease or this
              Sublease by any trustee in bankruptcy, or by the Sublandlord
              ceasing to exist (whether by winding up, forfeiture, cancellation
              or surrender of its charter, merger or any other circumstances);

         (g)  to permit the use by the Subtenant of certain segments of the
              Intrusion Detection/Access Control System to be designated by the
              Sublandlord as such relate to the Sublet Premises, at no cost to
              the Sublandlord. However, the Sublandlord makes no representations
              or warranties regarding the fitness of such system for use by the
              Subtenant or the ongoing performance of such system for the use of
              the Subtenant;

         (h)  to permit the use by the Subtenant of the cafeteria in the
              Building under the same terms and conditions as the Sublandlord
              for so long as the Sublandlord shall occupy the Building;

         (i)  to permit the use by the Subtenant of the fitness centre (i.e.,
              Zarfit) under the same terms and conditions as offered to
              employees of the Sublandlord;

         (j)  to provide fifteen tons of cooling to the Laboratory Space;

         (k)  to indemnify and save harmless the Subtenant against and from any
              and all expenses, costs, damages, suits, actions or liabilities
              ("Costs") arising out of the failure of the Sublandlord to perform
              any of its obligations hereunder and from all claims and demands
              of every kind and nature ("Claims") made by any person or persons
              to or against the Subtenant for all and every manner of Costs
              incurred by or injury or damage to such person or persons or his,
              her or their property, if such Claims arise out of any act or
              omission of the Sublandlord or any other person authorized by the
              Sublandlord and from all Costs incurred in and about any such
              Claim or any action or proceeding brought thereon, except to the
              extent such Costs or Claims arise out of or are caused by or
              attributable to an act or omission of the Subtenant or those for
              whom it is at law responsible;



                                      -10-

         (l)  that it has dealt with no broker, finder, agent or other person in
              connection with the Sublease other than Colliers Macaulay Nicolls
              (Ontario) Inc. (the "Sublandlord Brokers"), and it agrees to
              indemnify and hold the Subtenant and Head Landlord harmless from
              and against any claims or causes of action for a commission or
              other form of compensation arising from this Sublease, whether
              advanced by the Sublandlord Brokers or any other person or entity.
              The provisions of this paragraph shall survive the termination of
              the Head Lease, this Sublease and any renewal or extension of
              either or both of them.

14.      Use and Access

Notwithstanding the definitions of "Permitted Use" and "Business" contained in
the Head Lease, the Head Landlord and the Sublandlord agree that the Subtenant
shall be permitted to use the Sublet Premises for the purposes of general
business offices, which may include without limitation software sales (it being
agreed and understood, however, that the Sublet Premises may not be used for
commercial sales to the general public), marketing and development, and a
software development computer laboratory in the Laboratory Space. The Sublet
Premises may be accessed by the Subtenant and its directors, officers, employees
and invitees on a 24 hour per day, 7 days per week basis.

15.      Parking

The Subtenant shall have the right, free of charge, to use 3.5 parking spaces
located at the Complex per 1,000 square feet of Sublet Premises.

16.      Insurance

The Subtenant shall take out and maintain throughout the Subterm insurance with
respect to the Sublet Premises upon the terms required of the Sublandlord in the
Head Lease and both the Head Landlord and the Sublandlord shall be shown as
additional insureds on all such policies. In addition to the foregoing
obligations, the Subtenant shall obtain liability insurance in an amount
satisfactory to the Sublandlord, acting reasonably, to cover any possible claims
arising from the use of the Sublandlord's cafeteria or fitness centre (i.e.,
Zarfit).

17.      Subtenant's Assigning, Subletting, Etc.

The Subtenant agrees that with respect to any assigning or subletting by it, the
provisions of the Head Lease apply with the following amendments thereto:

         (a)  each reference to the Landlord, the Tenant, the Lease and the
              Leased Premises shall become, respectively, the Sublandlord, the
              Subtenant, the Sublease and the Sublet Premises; and



                                      -11-

         (b)  the Sublandlord shall have the additional right to withhold and/or
              delay its consent if it has not received the consent of the Head
              Landlord.

18.      Other Terms of Head Lease Incorporated

Subject to the provisions of this Sublease, the specific sections of the Head
Lease which are incorporated elsewhere in this Sublease and subject to the
exceptions to subsection 112(a), all of the terms of the Head Lease are also
incorporated, mutatis mutandis, into and apply to this Sublease with each
reference to the Landlord in the Head Lease being deemed to include both the
Head Landlord and the Sublandlord and with each reference therein to the Tenant
being deemed to mean the Subtenant. If any term of this Sublease is inconsistent
with any term of the Head Lease, the term of this Sublease shall prevail.

19.      Exercise of Rights

Subject to the provisions of this Sublease, the exercise by the Head Landlord of
any of its rights contained in the Head Lease shall, upon written notice by the
Head Landlord to the Subtenant of such exercise, be binding upon the Subtenant.
Notwithstanding the exercise by the Head Landlord of any of its rights contained
in the Head Lease, the Sublandlord may also exercise its rights hereunder in the
same manner as the Head Landlord.

20.      Termination of Head Lease

Subject to the provisions of this Sublease, the Subtenant acknowledges and
agrees that it has no greater interest in the Sublet Premises than the
Sublandlord under the Head Lease.

21.      Notices and Consents, Etc.

Except as otherwise specifically provided herein, any notice or consent
including any invoice, statement or request or other communication (a "Notice")
herein required or permitted to be given by either party to the other shall be
in writing and shall be delivered by hand or sent by double registered mail
(except during a postal disruption or threatened postal disruption) or by
facsimile to the applicable address (and facsimile number, if applicable) set
forth below:

         (a)  in the case of the Sublandlord, to:


              Zarlink Semiconductor Inc.
              400 March Road
              Ottawa, Ontario  K2K 3H4

              Attention:  General Counsel

              Facsimile:  (613) 592-1010



                                      -12-

              with a copy to:


              Zarlink Semiconductor Inc.
              400 March Road
              Ottawa, Ontario  K2K 3H4


              Attention:   Mr. Kevin Jones, Manager, Facilities, Engineering and
                           Real Estate


              Facsimile:  (613) 592-1010


         (b)  in the case of the Subtenant:


              MetaSolv, Inc.
              5560 Tennyson Parkway
              Plano, Texas 75024



              Attention:   General Counsel, with a copy to Purchasing Department


              Facsimile:  (972) 403-8989


Any Notice delivered by hand shall be deemed to have been validly and
effectively given on the day of such delivery if delivered before 4:00 p.m. on a
Business Day or on the next Business Day if delivered on a non-Business Day or
after 4:00 p.m. on the previous Business Day. Any Notice sent by double
registered mail (except during a postal disruption or threatened postal
disruption) shall be deemed to have been validly and effectively given on the
third Business Day following the date of mailing. Any Notice sent by facsimile
shall be deemed to have been validly and effectively given on the day it was
sent if sent before 4:00 p.m. on a Business Day or on the next Business Day if
sent on a non-Business Day or after 4:00 p.m. on the previous Business Day.

Any party may from time to time by Notice to the other parties change its
address for service hereunder.

22.      Successors and Assigns

Except as otherwise provided herein, all of the rights and obligations of a
party hereto, including any rights of a personal nature, enure to the benefit of
and are binding upon the successors and assigns of that party.

23.      Further Assurances

Each of the parties hereto agrees to do, make and execute all such further
documents, agreements, assurances, acts, matters and things and take such
further action as may be reasonably required by any other party hereto in order
to more effectively carry out the true intent of this Sublease. This Sublease
(except paragraph 6) shall not be effective until the Head



                                      -13-

Landlord has delivered its consent to this Sublease. Paragraph 6 shall be
effective as between the Sublandlord and the Subtenant when this Sublease has
been executed by them.

24.      Governing Law

This Agreement is a contract made under and shall be governed by and construed
in accordance with the law of the Province of Ontario and the federal laws of
Canada applicable in the Province of Ontario.

The remainder of this page intentionally left blank. Signature page follows.



                                      -14-

IN WITNESS OF WHICH the parties have duly executed this Sublease.

                                    ZARLINK SEMICONDUCTOR INC.

                                    By:   /s/  Tim Saunders
                                       ----------------------------------
                                       Name:   Tim Saunders
                                       Title: V.P. & Corporate Controller

                                    By:   /s/ Dan MacIntyre
                                       ----------------------------------
                                       Name: Dan MacIntyre
                                       Title: Sr.V.P.


                                    I/We have authority to bind the corporation.

                                    METASOLV SOFTWARE CANADA, INC.

                                    By:   /s/  Jonathan K. Hustis
                                       ----------------------------------
                                       Name:  Jonathan K. Hustis
                                       Title:    Secretary

                                    By:
                                       ----------------------------------
                                       Name:
                                       Title:


                                    I/We have authority to bind the corporation.



                                   SCHEDULE A

                                   HEAD LEASE



                                   SCHEDULE B

                    FLOOR PLAN SHOWING SUBLET PREMISES SHADED


                                  [FLORR PLAN]



                                   SCHEDULE C

                       FORM OF SUBTENANT LETTER OF CREDIT

                                LETTER OF CREDIT

Letter of Credit Reference No. ______________

Beneficiary:      MetaSolv Software Canada Inc.
                  c/o MetaSolv, Inc.
                  5560 Tennyson Parkway
                  Plano, Texas 75024
                  Attention: General Counsel

Applicant: Zarlink Semiconductor Inc.

Amount:  CAD $250,000.00  (Two Hundred and Fifty Thousand Canadian Dollars)

Date of Expiry: _______ (at ____ p.m. at the Bank's counters at the address
                noted below)

1.   Pursuant to the request of Zarlink Semiconductor Inc. (the "Applicant"),
     _________________________________ (the "Bank") through its branch or office
     located at the address noted below hereby establishes an irrevocable
     standby letter of credit in favour of MetaSolv Software Canada Inc. and its
     assigns (collectively, the "Beneficiary") for the maximum amount of CAD
     $250,000.00 (Two Hundred and Fifty Thousand Canadian Dollars).

2.   This letter of credit is available for payment against receipt by the Bank
     at the above address of the following documents:

     (a)  the Beneficiary's certificate signed by an officer or director of the
          Beneficiary, referencing this letter of credit number and date and the
          amount claimed, and stating that the Beneficiary is entitled to
          payment of the amount claimed in accordance with the terms of a
          Sublease made as of the 4th day of June, 2002 made between the
          Applicant and the Beneficiary (the "Sublease"); and

     (b)  this original letter of credit for the Bank's endorsement of any
          payment thereon.

3.   Partial drawings are not permitted.

4.   This letter of credit will not be released, discharged or affected by the
     bankruptcy, receivership or insolvency of the Applicant, by any disclaimer
     of the Sublease by any trustee in bankruptcy or by the Applicant ceasing to
     exist (whether by winding-up, forfeiture, cancellation or surrender of its
     charter, merger or any other circumstances).

5.   The Bank agrees that a demand presented to the Bank in compliance with the
     terms of this letter of credit will be duly honoured without enquiring
     whether the Beneficiary has the right as between itself and the Applicant
     to make such demand and without recognizing any claim of the Applicant.

6.   It is a condition of this letter of credit that it will be deemed to be
     automatically extended, without amendment, for one (1) year from the
     present or any future expiration date hereof, unless at least thirty (30)
     days prior to any such date the Bank notifies the Beneficiary in writing by
     registered mail or courier that the Bank elects not to consider this letter
     of credit extended for any such additional period.



                                      -2-

7.   This letter of credit is subject to the "Uniform Customs and Practice for
     Documentary Credits (1993 Revision) International Chamber of Commerce,
     Publication No. 500" and engages the Bank in accordance with the terms
     thereof.



                                            _____________________________
                                            (name of the Bank)

_______________________________             _____________________________
Counter Signature                           Authorized Signature

                                            Address of Bank:

                                            _____________________________

                                            _____________________________