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                                                                     Exhibit 3.1

                        SX CERTIFICATE OF INCORPORATION

                                       OF

                                  ADAPTEC, INC.


                                   ARTICLE ONE

        The name of the Corporation is Adaptec, Inc. (the "Corporation").

                                   ARTICLE TWO

        The address of the Corporation's registered office in the State of
Delaware is Corporation Trust Center, 1209 Orange Street, in the City of
Wilmington, County of New Castle, zip code 19801. The name of its registered
agent at such address is The Corporation Trust Company.

                                  ARTICLE THREE

        The purpose of the Corporation is to engage in any lawful act or
activity for which corporations may be organized under the General Corporation
Law of Delaware.

                                  ARTICLE FOUR

        Part 1. Authorized Capital Stock. This Corporation is authorized to
issue two classes of shares of stock to be designated, respectively, "Common
Stock" and "Preferred Stock." The total number of shares which the Corporation
is authorized to issue is 401,000,000 shares consisting of:

               (i)  400,000,000 shares of Common Stock, $.001 per share par 
value; and

               (ii) 1,000,000 shares of Preferred Stock, $.001 per share par
value of which Two-Hundred Fifty Thousand (250,000) shares have been designated
Series A Participating Preferred Stock.

        Part 2. Undesignated Preferred Stock. The Board of Directors is hereby
authorized, subject to limitations prescribed by the Corporation Law, to provide
for the issuance of the shares of undesignated Preferred Stock in one or more
series, and by filing a certificate pursuant to the Corporation Law, to
establish from time to time the number of shares to be included in each such
series, and to fix the designation, powers, preferences and rights of the shares
of each such series and the qualifications, limitations or restrictions thereof.

               The authority of the Board of Directors with respect to each
series of undesignated Preferred Stock shall include, but not be limited to,
determination of the following:
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               (i) the number of shares constituting that series and the 
distinctive designation of that series;

               (ii) the dividend rate on the shares of that series, whether
dividends shall be cumulative, and if so, from which date or dates, and the
relative rights of priority, if any, of payment of dividends on shares of that
series;

               (iii) whether that series shall have voting rights in addition to
the voting rights provided by law, and if so, the terms of such voting rights;

               (iv) whether that series shall have conversion privileges, and if
so, the terms and conditions of such privileges, including provision for
adjustment of the conversion rate in such events as the Board of Directors shall
determine;

               (v) whether or not the shares of that series shall be redeemable,
and if so, the terms and conditions of such redemption, including the date or
dates upon or after which they shall be redeemable, and the amount per share
payable in case of redemption, which amount may vary under different conditions
and at different redemption rates;

               (vi) whether that series shall have a sinking fund for the
redemption or purchase of shares of that series, and if so, the terms in the
amount of such sinking funds;

               (vii) the rights of the shares of that series in the event of
voluntary or involuntary liquidation, dissolution or winding up of the
Corporation, and the relative rights of priority, if any, of payment of shares
of that series; and

               (viii) any other relative rights, preferences and limitations of
that series.

        Unless otherwise provided in the certificate establishing the
designation, powers, preferences, and rights of shares of Undesignated Preferred
Stock, the number of shares of any series of Undesig nated Preferred Stock may
be increased (but not above the total number of authorized shares of
Undesignated Preferred Stock) or decreased (but not below the number of shares
thereof then outstanding) by a certificate pursuant to the Corporation Law. In
case the number of shares of any series of Undesignated Preferred Stock shall be
decreased, the shares constituting such decrease shall resume the status which
they had prior to the adoption of the resolution originally fixing the number of
shares of such series of Undesignated Preferred Stock.

        Part 3. Series A Participating Preferred Stock. The Series A
Participating Preferred Stock shall have the following designations, powers,
preferences and relative and other special rights and qualifications,
limitations and restrictions:

               (i) Proportional Adjustment. In the event the Corporation shall
at any time after the issuance of any share or shares of Series A Participating
Preferred Stock (a) declare any dividend on Common Stock of the Corporation
("Common Stock") payable in shares of Common Stock, (b) subdivide the
outstanding Common Stock or (c) combine the outstanding Common Stock into a
smaller number of shares, then in each such case the Corporation shall
simultaneously effect a

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proportional adjustment to the number of outstanding shares of Series A
Participating Preferred Stock.

               (ii) Dividends and Distributions.

                      (a) Subject to the prior and superior right of the holders
of any shares of any series of Preferred Stock ranking prior and superior to the
shares of Series A Participating Preferred Stock with respect to dividends, the
holders of shares of Series A Participating Preferred Stock shall be entitled to
receive when, as and if declared by the Board of Directors out of funds legally
available for the purpose, quarterly dividends payable in cash on the last day
of January, April, July and October in each year (each such date being referred
to herein as a "Quarterly Dividend Payment Date"), commencing on the first
Quarterly Dividend Payment Date after the first issuance of a share or fraction
of a share of Series A Participating Preferred Stock, in an amount per share
(rounded to the nearest cent) equal to 1,000 times the aggregate per share
amount of all cash dividends, and 1,000 times the aggregate per share amount
(payable in kind) of all non-cash dividends or other distributions other than a
dividend payable in shares of Common Stock or a subdivision of the outstanding
shares of Common Stock (by reclassification or otherwise), declared on the
Common Stock since the immediately preceding Quarterly Dividend Payment Date,
or, with respect to the first Quarterly Dividend Payment Date, since the first
issuance of any share or fraction of a share of Series A Participating Preferred
Stock.

                      (b) The Corporation shall declare a dividend or
distribution on the Series A Participating Preferred Stock as provided in
paragraph (a) above immediately after it declares a dividend or distribution on
the Common Stock (other than a dividend payable in shares of Common Stock).

                      (c) Dividends shall begin to accrue on outstanding shares
of Series A Participating Preferred Stock from the Quarterly Dividend Payment
Date next preceding the date of issue of such shares of Series A Participating
Preferred Stock, unless the date of issue of such shares is prior to the record
date for the first Quarterly Dividend Payment Date, in which case dividends on
such shares shall begin to accrue from the date of issue of such shares, or
unless the date of issue is a Quarterly Dividend Payment Date or is a date after
the record date for the determination of holders of shares of Series A
Participating Preferred Stock entitled to receive a quarterly dividend and
before such Quarterly Dividend Payment Date, in either of which events such
dividends shall begin to accrue from such Quarterly Dividend Payment Date.
Accrued but unpaid dividends shall not bear interest. Dividends paid on the
shares of Series A Participating Preferred Stock in an amount less than the
total amount of such dividends at the time accrued and payable on such shares
shall be allocated pro rata on a share-by-share basis among all such shares at
the time outstanding. The Board of Directors may fix a record date for the
determination of holders of shares of Series A Participating Preferred Stock
entitled to receive payment of a dividend or distribution declared thereon,
which record date shall be no more than 30 days prior to the date fixed for the
payment thereof.


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               (iii) Voting Rights. The holders of shares of Series A
Participating Preferred Stock shall have the following voting rights:

                      (a) Each share of Series A Participating Preferred Stock
shall entitle the holder thereof to 1,000 votes on all matters submitted to a
vote of the stockholders of the Corporation.

                      (b) Except as otherwise provided herein or by law, the
holders of shares of Series A Participating Preferred Stock and the holders of
shares of Common Stock shall vote together as one class on all matters submitted
to a vote of stockholders of the Corporation.

                      (c) Except as required by law, holders of Series A
Participating Preferred Stock shall have no special voting rights and their
consent shall not be required (except to the extent they are entitled to vote
with holders of Common Stock as set forth herein) for taking any corporate
action.

               (iv) Certain Restrictions.

                      (a) The Corporation shall not declare any dividend on,
make any distribution on, or redeem or purchase or otherwise acquire for
consideration any shares of Common Stock after the first issuance of a share or
fraction of a share of Series A Participating Preferred Stock unless
concurrently therewith it shall declare a dividend on the Series A Participating
Preferred Stock as required by Section (ii) hereof.

                      (b) Whenever quarterly dividends or other dividends or
distributions payable on the Series A Participating Preferred Stock as provided
in Section (ii) are in arrears, thereafter and until all accrued and unpaid
dividends and distributions, whether or not declared, on shares of Series A
Participating Preferred Stock outstanding shall have been paid in full, the
Corporation shall not:

                             1. declare or pay dividends on, make any other
distributions on, or redeem or purchase or otherwise acquire for consideration
any shares of stock ranking junior (either as to dividends or upon liquidation,
dissolution or winding up) to the Series A Participating Preferred Stock;

                             2. declare or pay dividends on, make any other
distributions on any shares of stock ranking on a parity (either as to dividends
or upon liquidation, dissolution or winding up) with Series A Participating
Preferred Stock, except dividends paid ratably on the Series A Participating
Preferred Stock and all such parity stock on which dividends are payable or in
arrears in proportion to the total amounts to which the holders of all such
shares are then entitled;

                             3. redeem or purchase or otherwise acquire for
consideration shares of any stock ranking on a parity (either as to dividends or
upon liquidation, dissolution or winding up) with the Series A Participating
Preferred Stock, provided that the Corporation may at 

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any time redeem, purchase or otherwise acquire shares of any such parity stock
in exchange for shares of any stock of the Corporation ranking junior (either as
to dividends or upon dissolution, liquidation or winding up) to the Series A
Participating Preferred Stock;

                             4. purchase or otherwise acquire for consideration
any shares of Series A Participating Preferred Stock, or any shares of stock
ranking on a parity with the Series A Participating Preferred Stock, except in
accordance with a purchase offer made in writing or by publication (as
determined by the Board of Directors) to all holders of such shares upon such
terms as the Board of Directors, after consideration of the respective annual
dividend rates and other relative rights and preferences of the respective
series and classes, shall determine in good faith will result in fair and
equitable treatment among the respective series or classes.

                      (c) The Corporation shall not permit any subsidiary of the
Corporation to purchase or otherwise acquire for consideration any shares of
stock of the Corporation unless the Corporation could, under paragraph (a) of
this Section (iv), purchase or otherwise acquire such shares at such time and in
such manner.

               (v) Reacquired Shares. Any shares of Series A Participating
Preferred Stock purchased or otherwise acquired by the Corporation in any manner
whatsoever shall be retired and canceled promptly after the acquisition thereof.
All such shares shall upon their cancellation become authorized but unissued
shares of Preferred Stock and may be reissued as part of a new series of
Preferred Stock to be created by resolution or resolutions of the Board of
Directors, subject to the conditions and restrictions on issuance set forth
herein.

               (vi) Liquidation, Dissolution or Winding Up. Upon any
liquidation, dissolution or winding up of the Corporation, the holders of shares
of Series A Participating Preferred Stock shall be entitled to receive an
aggregate amount per share equal to 1,000 times the aggregate amount to be
distributed per share to holders of shares of Common Stock plus an amount equal
to any accrued and unpaid dividends on such shares of Series A Participating
Preferred Stock.

               (vii) Consolidation, Merger, etc. In case the Corporation shall
enter into any consolidation, merger, combination or other transaction in which
the shares of Common Stock are exchanged for or changed into other stock or
securities, cash and/or any other property, then in any such case the shares of
Series A Participating Preferred Stock shall at the same time be similarly
exchanged or changed in an amount per share equal to 1,000 times the aggregate
amount of stock, securities, cash and/or any other property (payable in kind),
as the case may be, into which or for which each share of Common Stock is
changed or exchanged.

               (viii) No Redemption. The shares of Series A Participating
Preferred Stock shall not be redeemable.

               (ix) Ranking. The Series A Participating Preferred Stock shall
rank junior to all other series of the Corporation's Preferred Stock as to the
payment of dividends and the distribution of assets, unless the terms of any
such series shall provide otherwise.

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               (x) Amendment. The Certificate of Incorporation of the
Corporation shall not be further amended in any manner which would materially
alter or change the powers, preference or special rights of the Series A
Participating Preferred Stock so as to affect them adversely without the
affirmative vote of the holders of a majority of the outstanding shares of
Series A Participating Preferred Stock, voting separately as a class.

               (xi) Fractional Shares. Series A Participating Preferred Stock
may be issued in fractions of a share which shall entitle the holder, in
proportion to such holder's fractional shares, to exercise voting rights,
receive dividends, participate in distributions and to have the benefit of all
other rights of holders of Series A Participating Preferred Stock.

                                  ARTICLE FIVE

        The name and mailing address of the incorporator are as follows:

                      Wady H. Milner
                      Wilson Sonsini Goodrich & Rosati, Professional Corporation
                      650 Page Mill Road
                      Palo Alto, CA  94304

                                   ARTICLE SIX

        The Corporation is to have perpetual existence.

                                  ARTICLE SEVEN

        The election of directors need not be by written ballot except to the
extent provided in the Bylaws.

                                  ARTICLE EIGHT

        The number of directors which constitute the whole Board of Directors of
the Corporation shall be designated in the Bylaws of the Corporation.

                                  ARTICLE NINE

        In furtherance and not in limitation of the powers conferred by the laws
of the State of Delaware, the Board of Directors is expressly authorized to
adopt, alter, amend or repeal the Bylaws of the Corporation, but the
stockholders may make additional Bylaws and may alter or repeal any Bylaw
whether adopted by them or otherwise.

                                   ARTICLE TEN

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        A director of the Corporation shall not be personally liable to the
Corporation or its stockholders for monetary damages for breach of fiduciary
duty as a director, except for liability (i) for any breach of the director's
duty of loyalty to the Corporation or its stockholders, (ii) for acts or
omissions not in good faith or which involve intentional misconduct or a knowing
violation of law, (iii) under Section 174 of the Delaware General Corporation
Law, or (iv) for any transaction from which the director derived any improper
personal benefit, and to the extent such exemption from liability or limitation
thereof is not permitted under the Delaware General Corporation Law as the same
exists or may hereafter be amended. If the Delaware General Corporation Law is
amended after the filing of this Certificate of Incorporation to authorize
corporate action further eliminating or limiting the personal liability of
directors, then the liability of a director of the Corporation shall be
eliminated or limited to the fullest extent permitted by the Delaware General
Corporation Law, as so amended.

        Neither any amendment nor repeal of this Article, nor the adoption of
any provision of this Certificate of Incorporation inconsistent with this
Article, shall eliminate or reduce the effect of this Article in respect of any
matter occurring, or any cause of action, suit or claim that, but for this
Article, would accrue or arise, prior to such amendment, repeal or adoption of
an inconsistent provision.

                                 ARTICLE ELEVEN

        Except as otherwise provided herein, at the election of directors of the
Corporation, each holder of Common Stock shall be entitled to one vote for each
share held. No stockholder will be permitted to cumulate votes at any election
of directors.

                                 ARTICLE TWELVE

        Meetings of stockholders may be held within or without the State of
Delaware, as the Bylaws may provide. The books of the Corporation may be kept
(subject to any provision contained in the laws of the State of Delaware)
outside of the State of Delaware at such place or places as may be designated
from time to time by the Board of Directors or in the Bylaws of the Corporation.

                                ARTICLE THIRTEEN

        The Corporation reserves the right to amend, alter, change or repeal any
provision contained in this Certificate of Incorporation, in the manner now or
hereafter prescribed by the laws of the State of Delaware, and all rights
conferred herein are granted subject to this reservation.






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        The undersigned incorporator hereby acknowledges that the foregoing
Certificate of Incorporation is her act and deed and that the facts stated
herein are true.


Dated:  November 19, 1997


                                                   -----------------------------
                                                   Wady H. Milner
                                                   Incorporator


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