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                                                                    EXHIBIT 10.1

                                 EMC CORPORATION

               1985 STOCK OPTION PLAN, as amended December 1, 1999

1. PURPOSE.

     The purpose of the EMC Corporation 1985 Stock Option Plan is to enable EMC
Corporation to provide a special incentive to a limited number of key employees
of the Company and its Subsidiaries, if any, who are in a position to have a
significant effect upon the Company's business and earnings. In order to
accomplish this purpose, the Plan authorizes the grant to such key employees of
options to purchase Common Stock of the Company. Increased ownership of Common
Stock will provide such key employees with an additional incentive to take into
account the long-term interests of the Company.

2. DEFINITIONS.

     As used herein, the following words or terms have the meanings set forth
below. The masculine gender is used throughout the Plan but is intended to apply
to members of both sexes.

     2.1  "Board of Directors" means the Board of Directors of the Company.

     2.2 "Code" means the Internal Revenue Code of 1986, as amended from time to
time, or any successor statute.

     2.3 "Committee" means the Committee appointed by the Board of Directors to
administer the Plan or the Board of Directors as a whole if no appointment is
made.

     2.4  "Common Stock" means the Common Stock of the Company.

     2.5 "Company" means EMC Corporation, a corporation established under the
laws of The Commonwealth of Massachusetts.

         2.6 "Fair Market Value" in the case of a share of Common Stock on a
particular day, means the fair market value as determined from time to time by
the Board of Directors or, where appropriate, by the Committee, taking into
account all information which the Board of Directors, or the Committee,
considers relevant.

     2.7 "Incentive Stock Option" means a stock option that satisfies the
requirements of Section 422 of the Code.

     2.8 "Participant" means an individual holding a stock option or stock
options granted to him under the Plan.


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     2.9 "Plan" means the EMC Corporation 1985 Stock Option Plan set forth
herein.

     2.10 "Subsidiary" or "Subsidiaries" means a corporation or corporations in
which the Company owns, directly or indirectly, stock possessing 50 percent or
more of the total combined voting power of all classes of stock.

     2.11 "Ten Percent Stockholder" means any person who, at the time an option
is granted, owns or is deemed to own stock (as determined in accordance with
Sections 422 and 424 of the Code) possessing more than ten percent (10%) of the
total combined voting power of all classes of stock of the Company or its parent
or a subsidiary.

3. ADMINISTRATION.

     3.1 The Plan shall be administered by the Committee and, to the extent
provided herein, the Board of Directors. A majority of the members of the
Committee shall constitute a quorum, and all determinations of the Committee
shall be made by a majority of its members. Any determination of the Committee
under the Plan may be made without notice or meeting of the Committee by a
writing signed by a majority of the Committee members.

     3.2 Subject to the provisions set forth herein, each of the Committee and
the Board of Directors shall have full authority to determine the provisions of
options to be granted under the Plan. Subject to the provisions set forth
herein, the Committee shall have full authority to interpret the terms of the
Plan and of options granted under the Plan, to adopt, amend and rescind rules
and guidelines for the administration of the Plan and for its own acts and
proceedings and to decide all questions and settle all controversies and
disputes which may arise in connection with the Plan; PROVIDED, HOWEVER, that
any change to the terms of an option granted hereunder shall be approved by the
Board of Directors to the extent such change would be deemed to be a new option
grant or such terms relate to a subsequent transaction that would not be exempt
from Section 16(b) of the Securities Exchange Act of 1934 in the absence of such
approval.

     3.3 The decision of the Committee or the Board of Directors, as applicable,
on any matter as to which the Committee or the Board of Directors, as
applicable, is given authority under subsection 3.2 shall be final and binding
on all persons concerned.

     3.4 Nothing in the Plan shall be deemed to give any officer or employee, or
his legal representatives or assigns, any right to participate in the Plan,
except to such extent, if any, as the Committee or the Board, as applicable, may
have determined or approved pursuant to the provisions of the Plan.


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4. SHARES SUBJECT TO THE PLAN.

     4.1 The maximum number of shares of Common Stock that may be delivered upon
the exercise of options granted under the Plan shall be 144,000,000, subject to
adjustment in accordance with the provisions of Section 8.

     4.2 If any option granted under the Plan terminates without having been
exercised in full (including an option which terminates by agreement between the
Company and the Participant), the number of shares of Common Stock as to which
such option has not been exercised prior to termination shall be available for
future grants within the limits set forth in subsection 4.1.

     4.3 Shares of Common Stock delivered upon the exercise of options shall
consist of shares of authorized and unissued Common Stock, except that the Board
of Directors may from time to time in its discretion determine in any case the
shares to be so delivered shall consist of shares of authorized and issued
Common Stock reacquired by the Company and held in its Treasury. No fractional
shares of Common Stock shall be delivered upon the exercise of an option.

5. ELIGIBILITY FOR OPTIONS.

     Employees eligible to receive options under the Plan shall be those key
employees of the Company and its Subsidiaries, if any, who, in the opinion of
the Committee, are in a position to have a significant effect upon the Company's
business and earnings. Members of the Board of Directors of the Company or a
Subsidiary who are not employed as regular salaried officers or employees of the
Company or a Subsidiary may not participate in the Plan.

6. GRANT OF OPTIONS.

     6.1 From time to time while the Plan is in effect, each of the Committee
and the Board of Directors may, in its absolute discretion, select from among
the persons eligible to receive options (including persons to whom options were
previously granted) those persons to whom options are to be granted.

     6.2 Each of the Committee and the Board of Directors shall, in its absolute
discretion, determine the number of shares of Common Stock to be subject to each
option granted by it under the Plan.

     6.3 No Incentive Stock Option may be granted under the Plan after May 16,
1995, but options theretofore granted may extend beyond that date.


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7. PROVISIONS OF OPTIONS.

     7.1 INCENTIVE STOCK OPTIONS OR OTHER OPTIONS. Options granted under the
Plan may be either Incentive Stock Options or options which do not qualify as
Incentive Stock Options, as the Committee or the Board of Directors shall
determine at the time of each grant of options hereunder.

     7.2 STOCK OPTION CERTIFICATES OR AGREEMENTS. Options granted under the Plan
shall be evidenced by certificates or agreements in such form as the Committee
shall from time to time approve. Such certificates or agreements shall comply
with the terms and conditions of the Plan and may contain such other provisions
not inconsistent with the terms and conditions of the Plan as the Committee
shall deem advisable. In the case of options intended to qualify as Incentive
Stock Options, the certificates or agreements shall contain such provisions
relating to exercise and other matters as are required of incentive stock
options under the Code.

     7.3 TERMS AND CONDITIONS. All options granted under the Plan shall be
subject to the following terms and conditions to the extent applicable and to
such other terms and conditions not inconsistent therewith as the Committee or
the Board of Directors shall determine:

          7.3.1 Exercise Price. The exercise price per share of Common Stock
     with respect to each option shall be as determined by the Committee but in
     the case of an Incentive Stock Option not less than 100% (110% in the case
     of an Incentive Stock Option granted to a Ten Percent Stockholder) of the
     Fair Market Value per share at the time the option is granted. In the case
     of an option which does not qualify as an Incentive Stock Option, the
     exercise price per share of Common Stock shall be not less than par value.
     However, for those employees subject to Section 16 of the Securities
     Exchange Act of 1934, the per share exercise price for an option which does
     not qualify as an Incentive Stock Option shall not be less than 50% of the
     Fair Market Value at the time the option is granted.

          7.3.2 VALUE OF SHARES OF COMMON STOCK SUBJECT TO INCENTIVE STOCK
     OPTIONS. Each eligible employee may be granted Incentive Stock Options only
     to the extent that, in the aggregate under this Plan and all incentive
     stock option plans of the Company and any related corporation, such
     Incentive Stock Options do not become exercisable for the first time by
     such employee during any calendar year in a manner which would entitle the
     employee to purchase more than $100,000 in fair market value (determined at
     the time the Incentive Stock Options were granted) of Common Stock in that
     year. Any options granted to any employee in excess of such amount will be
     granted as Non-Qualified Options.

          7.3.3 PERIOD OF OPTIONS. An option shall be exercisable during such
     period of time as the Committee or the Board of Directors may specify
     (subject to subsection 7.4 below), but in the case of an Incentive Stock
     Option not after the


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     expiration of ten years (five years in the case of an Incentive Stock
     Option granted to a Ten Percent Stockholder) from the date the option is
     granted.

          7.3.4 EXERCISE OF OPTIONS.

               7.3.4.1 Each option shall be made exercisable at such time or
          times as the Committee or the Board of Directors shall determine. In
          the case of an option made exercisable in installments, the Committee
          or the Board of Directors may later determine to accelerate the time
          at which one or more of such installments may be exercised.

               7.3.4.2 Any exercise of an option shall be in writing signed by
          the proper person and delivered or mailed to the General Counsel of
          the Company, accompanied by an option exercise notice and payment in
          full for the number of shares in respect to which the option is
          exercised.

               7.3.4.3 In the event an option is exercised by the executor or
          administrator of a deceased Participant, or by the person or persons
          to whom the option has been transferred by the Participant's will or
          the applicable laws of descent and distribution, the Company shall be
          under no obligation to deliver stock thereunder until the Company is
          satisfied that the person or persons exercising the option is or are
          the duly appointed executor or administrator of the deceased
          Participant or the person or persons to whom the option has been
          transferred by the Participant's will or by the applicable laws of
          descent and distribution.

               7.3.4.4 The Committee or the Board of Directors may at the time
          of grant condition the exercise of an option upon agreement by the
          Participant to subject the Common Stock to any restrictions on
          transfer or repurchase rights in effect on the date of exercise, upon
          representations of continued employment and upon other terms not
          inconsistent with this Plan. Any such conditions shall be set forth in
          the option certificate or other document evidencing the option.

               7.3.4.5 In the case of an option that is not an Incentive Stock
          Option, the Committee shall have the right to require that the
          individual exercising the option to remit to the Company an amount
          sufficient to satisfy any federal, state, or local withholding tax
          requirements (or makes other arrangements satisfactory to the Company
          with regard to such taxes) prior to the delivery of any Common Stock
          pursuant to the exercise of the option. In the case of an Incentive
          Stock Option, if at the time the Incentive Stock Option is exercised
          the Committee determines that under applicable law and regulations the
          Company could be liable for the withholding of any federal or state
          tax with respect to a disposition of the Common Stock received upon
          exercise, the Committee may require as a


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          condition of exercise that the individual exercising the Incentive
          Stock Option agree (i) to inform the Company promptly of any
          disposition (within the meaning of Section 422 (a) (1) of the Code and
          the regulations thereunder) of Common Stock received upon exercise,
          and (ii) to give such security as the Committee deems adequate to meet
          the potential liability of the Company for the withholding of tax, and
          to augment such security from time to time in any amount reasonably
          deemed necessary by the Committee to preserve the adequacy of such
          security.

               7.3.4.6 In the case of an option that is exercised by an
          individual that is subject to taxation in a foreign jurisdiction, the
          Committee shall have the right to require the individual exercising
          the option to remit to the Company an amount sufficient to satisfy any
          federal or withholding requirement of that foreign jurisdiction (or
          make other arrangements satisfactory to the Company with regard to
          such taxes prior to the delivery of any Common Stock pursuant to the
          exercise of the option).

          7.3.5 PAYMENT FOR AND DELIVERY OF STOCK. The shares of stock purchased
on any exercise of an option granted hereunder shall be paid for in full in cash
or, if permitted by the terms of the option, in shares of unrestricted Common
Stock at the time of such exercise or, if so permitted, a combination of such
cash and Common Stock. A Participant shall not have the rights of a stockholder
with respect to awards under the Plan except as to stock actually issued to him.

          7.3.6 LISTING OF STOCK, WITHHOLDING AND OTHER LEGAL REQUIREMENTS. The
Company shall not be obligated to deliver any stock until all federal and state
laws and regulations which the Company may deem applicable have been complied
with, nor, in the event the outstanding Common Stock is at the time listed upon
any stock exchange, until the stock to be delivered has been listed or
authorized to be added to the list upon official notice of issuance to such
exchange. In addition, if the shares of stock subject to any option have not
been registered in accordance with the Securities Act of 1933, as amended, the
Company may require the person or persons who wishes or wish to exercise such
option to make such representation or agreement with respect to the sale of
stock acquired on exercise of the option as will be sufficient, in the opinion
of the Company's counsel, to avoid violation of said Act, and may also require
that the certificates evidencing said stock bear an appropriate restrictive
legend.

          7.3.7 NON-TRANSFERABILITY OF OPTIONS. No option may be transferred by
the Participant otherwise than by will, by the laws of descent and distribution
or pursuant to a qualified domestic relations order, and during the
Participant's lifetime the option may be exercised only by him or her; PROVIDED,
HOWEVER, that the Board of Directors or the Committee, as applicable, in its
discretion, may allow for transferability of non-qualified stock options by the
Participant to "Immediate Family Members". Immediate Family Members means
children,


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grandchildren, spouse or common law spouse, siblings or parents of the
Participant or to bona fide trusts, partnerships or other entities controlled by
and of which the beneficiaries are Immediate Family Members of the Participant.
Any option grants that are transferable are further conditioned on the
Participant and Immediate Family Members agreeing to abide by the Company's then
current stock option transfer guidelines.

     7.3.8 DEATH. If a Participant dies at a time when he is entitled to
exercise an Incentive Stock Option, then at any time or times within three years
after his death such Incentive Stock Option may be exercised, as to all or any
of the shares which the Participant was entitled to purchase thereunder
immediately prior to his death, by his executor or administrator or the person
or persons to whom the Incentive Stock Option is transferred by will or the
applicable laws of descent and distribution, and except as so exercised such
Incentive Stock Option shall expire at the end of such three-year period. In no
event, however, may any Incentive Stock Option granted under the Plan be
exercised after the expiration of ten years (five years in the case of an
Incentive Stock Option granted to a Ten Percent Stockholder) from the date the
Incentive Stock Option was granted.

     7.3.9 TERMINATION OF EMPLOYMENT. If the employment of a Participant
terminates for any reason other than his death, all options held by the
Participant shall thereupon expire on the date of termination unless the option
by its terms, or the Committee or the Board of Directors by resolution, shall
allow the Participant to exercise any or all of the options held by him after
termination. In the case of an Incentive Stock Option, the Incentive Stock
Option shall in any event expire at the end of three months after such
termination of employment, or after the expiration of ten years (five years in
the case of an Incentive Stock Option granted to a Ten Percent Stockholder) from
the date the Incentive Stock Option was granted, whichever occurs first. If the
Committee or the Board of Directors so decides, an option may provide that a
leave of absence granted by the Company or Subsidiary is not a termination of
employment for the purpose of this subsection 7.3.9, and in the absence of such
a provision the Committee may in any particular case determine that such a leave
of absence is not a termination of employment for such purpose. The Committee
shall also determine all other matters relating to continuous employment.

     7.3.10 CANCELLATION AND RESCISSION OF OPTIONS. The following provisions of
this Section 7.3.10 shall apply to options granted on or after July 1, 1998 to
(i) Participants who are classified by the Company or a Subsidiary as an
executive officer, senior officer, or officer (collectively, an "Officer") of
the Company or a Subsidiary; and (ii) certain other Participants designated by
the Committee or the Board of Directors to be subject to the terms of this
Section 7.3.10 (such designated Participants together with Officers referred to
collectively as "Senior Participants"). The Committee or the Board of Directors
may cancel, rescind, suspend or otherwise limit or restrict any unexpired option
at any time if the


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     Senior Participant engages in "Detrimental Activity" (as defined below).
     Furthermore, in the event a Senior Participant engages in Detrimental
     Activity at any time prior to or during the six months after any exercise
     of an option, such exercise may be rescinded until the later of (i) two
     years after such exercise or (ii) two years after such Detrimental
     Activity. Upon such rescission, the Company at its sole option may require
     the Senior Participant to (i) deliver and transfer to the Company the
     shares of Common Stock received by the Senior Participant upon such
     exercise, (ii) pay to the Company an amount equal to any realized gain
     received by the Senior Participant from such exercise, or (iii) pay to the
     Company an amount equal to the market price (as of the exercise date) of
     the Common Stock acquired upon such exercise minus the respective exercise
     price. The Company shall be entitled to set-off any such amount owed to the
     Company against any amount owed to the Senior Participant by the Company.
     As used in this subsection 7.3.10, "Detrimental Activity"shall include: (i)
     the failure to comply with the terms of the Plan or certificate or
     agreement evidencing the option; (ii) the failure to comply with any term
     set forth in the Company's Key Employee Agreement (irrespective of whether
     the Senior Participant is a party to the Key Employee Agreement); (iii) any
     activity that results in termination of the Senior Participant's employment
     for cause; (iv) a violation of any rule, policy, procedure or guideline of
     the Company; or (v) the Senior Participant being convicted of, or entering
     a guilty plea with respect to a crime whether or not connected with the
     Company.

          7.3.11 JURISDICTION AND GOVERNING LAW. The parties submit to the
     exclusive jurisdiction and venue of the federal or state courts of the
     Commonwealth of Massachusetts, County of Middlesex, to resolve issues that
     may arise out of or relate to the Plan or the same subject matter. The Plan
     shall be governed by the laws of the Commonwealth of Massachusetts,
     excluding its conflicts or choice of law rules or principles that might
     otherwise refer construction or interpretation of this Plan to the
     substantive law of another jurisdiction.

     7.4 AUTHORITY OF THE COMMITTEE. The Committee shall have the authority,
either generally or in particular instances, to waive compliance by a
Participant with any obligation to be performed by him under an option and to
waive any condition or provision of an option, except that the Committee may not
(i) increase the total number of shares covered by any Incentive Stock Option
(except in accordance with Section 8), (ii) reduce the option price per share of
any Incentive Stock Option (except in accordance with Section 8) or (iii) extend
the term of any Incentive Stock Option to more than ten years, subject, however,
to the provisions of Section 10.

8. CHANGES IN STOCK.

     In the event of a stock dividend, stock split or other change in corporate
structure or capitalization affecting the Common Stock that becomes effective
after the adoption of


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the Plan by the Board of Directors, the Committee shall make appropriate
adjustments in (i) the number and kind of shares of stock on which options may
thereafter be granted hereunder, (ii) the number and kind of shares of stock
remaining subject to each option outstanding at the time of such change and
(iii) the option price. The Committee's determination shall be binding on all
persons concerned. Subject to any required action by the stockholders, if the
Company shall be the surviving corporation in any merger or consolidation (other
than a merger or consolidation in which the Company survives but in which a
majority of its outstanding shares are converted into securities of another
corporation or are exchanged for other consideration), any option granted
hereunder shall pertain and apply to the securities which a holder of the number
of shares of stock of the Company then subject to the option would have been
entitled to receive, but a dissolution or liquidation of the Company or a merger
or consolidation in which the Company is not the surviving corporation or in
which a majority of its outstanding shares are so converted or exchanged shall
cause every option hereunder to terminate; provided that if any such
dissolution, liquidation, merger or consolidation is contemplated, the Company
shall either arrange for any corporation succeeding to the business and assets
of the Company to issue to the Participants replacement options (which, in the
case of Incentive Stock Options, satisfy, in the determination of the Committee,
the requirements of Section 424 of the Code) on such corporation's stock which
will to the extent possible preserve the value of the outstanding options or
shall make the outstanding options fully exercisable at least 20 days before the
effective date of any such dissolution, liquidation, merger or consolidation.
The existence of the Plan shall not prevent any such change or other transaction
and no Participant thereunder shall have any right except as herein expressly
set forth.

9.   EMPLOYMENT RIGHTS.

     Neither the adoption of the Plan nor any grant of options confers upon any
employee of the Company or a Subsidiary any right to continued employment with
the Company or a Subsidiary, as the case may be, nor does it interfere in any
way with the right of the Company or a Subsidiary to terminate the employment of
any of its employees at any time.

10.  DISCONTINUANCE, CANCELLATION, AMENDMENT AND TERMINATION.

     The Committee or the Board of Directors may at any time discontinue
granting options under the Plan and, with the consent of the Participant, may at
any time cancel an existing option in whole or in part and grant another option
to the Participant for such number of shares as the Committee or the Board of
Directors specifies. The Board of Directors may at any time or times amend the
Plan for the purpose of satisfying the requirements of any changes in applicable
laws or regulations or for any other purpose which may at the time be permitted
by law or may at any time terminate the Plan as to any further grants of
options, provided that no such amendment shall without the approval of the
stockholders of the Company (a) increase the maximum number of shares available


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under the Plan, (b) change the group of employees eligible to receive options
under the Plan, (c) reduce the exercise price of outstanding incentive options
or reduce the price at which incentive options may be granted, (d) extend the
time within which options may be granted, (e) alter the Plan in such a way that
incentive options granted or to be granted hereunder would not be considered
incentive stock options under Section 422 of the Code, or (f) amend the
provisions of this Section 10, and no such amendment shall adversely affect the
rights of any employee (without his consent) under any option previously
granted.

11.  EFFECTIVE DATE.

     The Plan shall become effective upon its adoption by the Board of
Directors, and options may be granted under the Plan from and after the date of
such adoption; provided, however, that if prior to May 16, 1986 the stockholders
of the Company have not approved the Plan, the Plan shall terminate to the
extent that it relates to the issuance of Incentive Stock Options and all
Incentive Stock Options theretofore granted shall terminate and cease to be of
any force or effect. No Incentive Stock Option granted hereunder shall be
exercisable unless and until the Plan has been so approved.