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                                                                    Exhibit 10.6


Confidential Materials omitted and filed separately with the Securities and
Exchange Commission. Asterisks denote omissions.

EMC/2/
The Enterprise Storage Company


              SUBCONTRACTOR AGREEMENT FOR PROFESSIONAL SERVICES
                                    BETWEEN
                            EMC CORPORATION ("EMC")
                                      AND
                     StorageNetworks Inc ("Subcontractor")
                     --------------------


This Subcontractor Agreement for Professional Services (hereinafter "Agreement")
is made on this 4th day of May 1999, between EMC Corporation, a Massachusetts
corporation with principal offices at 171 South Street, Hopkinton, Massachusetts
01748 ("EMC"), and StorageNetworks Inc, a Delaware corporation, with principal
offices at 100 Fifth Ave, Waltham Ma 02154, ("Subcontractor"), who hereby agree
to the following:

     1. Services. EMC may acquire the professional services of the
        ---------
Subcontractor, subject to the terms and conditions of this Agreement, which
shall be performed in conjunction with EMC's provision of services to an EMC
customer. The work to be performed by Subcontractor shall be set forth in a
Statement of Work to be signed and attached hereto as Schedule A to this
Agreement. Each Statement of Work shall contain at a minimum the following
information:

     a) a description of the services to be performed by the Subcontractor;
     b) the place of performance;
     c) the period of performance; and
     d) the fees to be paid.




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Confidential Materials omitted and filed separately with the Securities and
Exchange Commission. Asterisks denote omissions.


     2. Pricing. EMC herein sets agreed to pricing at $[**] per hour for SNI
        --------
services. This pricing level is based upon the SNI's commitment to procure and
implement EMC technology into their POP sites based on the following
schedule.....Houston site by Q2 end, NY site by Q3 end, Boston site by Q4 end
and San Fran site by Q4 end. (All dates are 1999). Inability to meet this
criteria will subject this pricing agreement to review by EMC.

     3. Payment. In consideration for Subcontractor's satisfactory work
        --------
referenced in Sections 9 & 10, EMC will pay Subcontrator according to the
payment terms set forth in the Statement of Work. Subcontractor shall submit
invoices on a monthly basis for services furnished during the preceding month,
unless otherwise stated, and each invoice shall reference the applicable
Statement of Work and shall include supporting detail and documentation of all
charges. All amounts are due and payable in U.S. dollars, unless otherwise
agreed by EMC in writing, within thirty (30) days from proper receipt of a
proper invoice. EMC shall not be obligated to pay submitted invoices until such
time as Subcontractor fails to submit invoices in accordance with the
documentation, payment and time requirements of this Section.

     4. Time and Materials. For Statements of Work to be performed on a Time and
        -------------------
Materials basis, EMC shall pay Subcontractor only in accordance with the
billable rates and expenses set forth in the Statement of Work and shall not be
liable for payments in excess of the funding limitations set forth therein.
Subcontractor shall notify EMC in writing at such time as the cumulative dollar
amount of billable labor and expenses reaches [**] percent ([**])% of the
estimated level of effort or funding limitation set forth therein and will
include in such notification an estimate of any additional labor hours and costs
needed to complete the requirements of the project. Subcontractor shall not be
obligated to provide, and EMC shall not be obligated to pay for, services or
expenses beyond the period of performance or in excess of the total funding
limitation specified in the Statement of Work.

     5. Firm Fixed Price. For Statements of Work to be performed on a Firm Fixed
        -----------------
Price basis, EMC shall not be obligated to pay Subcontractor in excess of the
Firm Fixed Price set forth in the Statement of Work. Subcontractor shall be
solely responsible for costs incurred by the Subcontractor in excess of the Firm
Fixed Price set forth therein.


                                       2
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     6. Expenses. EMC will reimburse Subcontractor for all out-of pocket
        ---------
expenses actually incurred by Subcontractor in rendering services under this
Agreement so long as such expenses are (a) necessary, reasonable and directly
related to work specified in the Statement of Work, (b) consistent with EMC's
then-current expense reimbursement policies, (which is a referenced addition to
this agreement), (c) not incurred under a Firm Fixed Price Statement of Work.
Notwithstanding the foregoing, Subcontractor shall be solely liable for payment
of all fees, licenses, bonds, taxes or other expenses required or imposed
against Subcontractor as a cost of doing business.

     7. Changes. EMC may request changes in the scope of work specified in the
        --------
Statement of Work. Upon agreement between the parties as to the changes and
associated price increase or decrease, EMC shall initiate an amendment in
writing to the existing Statement of Work. EMC shall not be obligated to pay for
any changed services and Subcontractor shall not be required to perform any
changed services in the absence of a duly executed amendment signed by the
parties.

     8. Non-Disclosure of Confidential and Proprietary Information. Upon
        -----------------------------------------------------------
execution of this Agreement, Subcontractor shall be bound by EMC's standard
"Non-Disclosure Agreement" and EMC shall be bound by SNI's standard
"Non-Disclosure Agreement which each shall execute as a condition to this
Agreement becoming effective. Copies shall be attached hereto and is
incorporated by reference.

     9. Title to Work Product. It is understood and agreed to by the parties
        ---------------------
that all effort expended and all results developed by EMC pursuant to this
Agreement, shall be and shall remain the property of EMC, who shall have the
sole and exclusive rights and title to any ideas developed, modified, changed,
improved, or utilized by Subcontractor as a result of this Agreement.
Subcontractor shall have the right and license to utilize the work product of
this Agreement, but all ownership rights are retained by EMC or its original
licensors, if any.


                                       3
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     10. Warranty. Subcontractor warrants that a) its professional services
         ---------
will be of professional quality and conform to generally accepted standards in
the industry; and b) its personnel shall be competent and qualified to perform
the tasks to which they are assigned.

     11. Performance. At all times during this Agreement, EMC reserves the right
         ------------
to reasonably determine, after mutual understanding is reached between both
parties, the quality of the Subcontractor's performance under this Agreement. In
the event that it is determined that any employee assigned to a particular
customer's site is unsuitable to perform the services requested, Subcontractor
shall promptly replace such employee after notification of such determination by
EMC.

     12. Independent Contractor. EMC and Subcontractor each agree that
         -----------------------
Subcontractor is, and shall remain, an independent contractor. Nothing in this
Agreement or a Statement of Work shall be construed to create or imply that any
either party is an agent of the other party. At no time shall either party make
any commitments or incur any expenses for, or in the name of, the other party
without the prior approval of the other party. Subcontractor's personnel are
not, nor shall they be deemed to be at any time during the term of this
Agreement, employees of EMC. Subcontractor will be solely responsible for
payment of all compensation owed to Subcontractor's personnel, as well as for
payment of employment related taxes and workers' compensation insurance.

     13. Non-Competition. Not applicable to this agreement.
         ----------------

     14. Indemnification. Not applicable to this agreement.
         ----------------

     15. Limitation of Liability. IN NO EVENT SHALL EITHER PARTY BE LIABLE TO
         ------------------------
THE OTHER PARTY FOR ANY SPECIAL, INDIRECT, OR CONSEQUENTIAL DAMAGES INCLUDING,
WITHOUT LIMITATION, LOST BUSINESS OR LOST PROFITS, WHETHER FORESEEABLE OR NOT,
EVEN IF THE PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES ARISING
OUT OF OR IN CONNECTION WITH THE PERFORMANCE OR NON-PERFORMANCE UNDER THIS
AGREEMENT.

                                       4



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     16. Termination. If either party breaches any material provision of
         ------------
this Agreement, the other party may terminate this Agreement upon thirty (30)
days prior written notice, provided the breach is not cured within such 30 day
period. Such termination shall not relieve either party from those of its
obligations hereunder that accrued prior to the date of termination, nor shall
it relieve the party in breach from any liability resulting therefrom.

     16.1 Either party may terminate this Agreement without cause with written
notice to the other party. EMC shall also have the right to immediately
terminate any Statement of Work or Schedule in the event EMC's customer
terminates its project or agreement with EMC.

     16.2 The provisions of Sections 7 (Non-Disclosure), 8 (Title to Work
Product), 9 (Warranty), 12 (Non-competition), 13 (Indemnification), and 14
(Limitation of Liability), shall survive termination of this Agreement.

     17. Notices. All notices, requests, authorizations, directions, or other
         --------
communications under this Agreement shall be given in writing by personal
delivery, by U.S. mail postage prepaid, or by facsimile with confirmed answer
back. Notice shall be effective upon delivery in the case of personal delivery,
on receipt in the case of facsimile, and five days after mailing in the case of
posting.

     18. Miscellaneous. This Agreement, Statements of Work, Schedules and the
         --------------
addendums hereto, if any, contain the entire understanding of the parties with
respect to the matters contained herein. There are no promises, covenants, or
undertakings other than those expressly set forth herein. This Agreement may not
be modified except by a writing, executed by authorized representatives of EMC
and Subcontractor. This Agreement is not assignable by Subcontractor without the
express written consent of either party. This Agreement shall be governed by the
laws, and enforceable in the courts, of the Commonwealth of Massachusetts,
U.S.A.

                                       5
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The parties hereby acknowledge that they have read and do understand this
Agreement and all addendums hereto, and agree to all terms and conditions stated
herein and attached hereto.


EMC Corporation                        StorageNetworks Inc.
                                       ---------------------------------
("EMC")                                ("Subcontractor")


/s/ David B Bedard                     /s/ Paul C Flanagan
--------------------------             --------------------------------
Signature                              Signature

DAVID B. BEDARD                        Paul Flanagan
--------------------------             ---------------------------------
Printed Name                           Printed Name

Sales Operations Mgr.                  CFO
--------------------------             ---------------------------------
Title                                  Title

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