8-A12B/A

                                   FORM 8-A/A

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                     ------

                FOR REGISTRATION OF CERTAIN CLASSES OF SECURITIES
                     PURSUANT TO SECTION 12(b) OR (g) OF THE
                         SECURITIES EXCHANGE ACT OF 1934

                            DATA GENERAL CORPORATION
            --------------------------------------------------------
             (Exact name of registrant as specified in its charter)


                 Delaware                                        04-2436397
- ----------------------------------------                   ---------------------
(State of incorporation or organization)                   (I.R.S. Employer
                                                            Identification No.)


 4400 Computer Drive
 Westboro, Massachusetts                                             01580
- ----------------------------------------                          ----------
(Address of principal executive offices)                          (Zip Code)


        Securities to be registered pursuant to Section 12(b)of the Act:

       Title of each class                        Name of each exchange on which
       to be so registered                        each class is to be registered
- -------------------------------                   ------------------------------
Preferred Stock Purchase Rights                       New York Stock Exchange
                                                       London Stock Exchange

     If this Form relates to the  registration of a class of debt securities and
is effective upon filing pursuant to General Instruction A.(c)(1),  please check
the following box. |_|

     If this Form relates to the  registration of a class of debt securities and
is to become  effective  simultaneously  with the  effectiveness of a concurrent
registration  statement  under the  Securities  Act of 1933  pursuant to General
Instruction A.(c)(2), please check the following box. |_|

        Securities to be registered pursuant to Section 12(g) of the Act:


                              None (Title of Class)



Item 1.  Description of Registrant's Securities to be Registered

                  On October 3, 1986,  the Board of  Directors  of Data  General
Corporation  (the "Company")  declared a dividend  distribution of one Right for
each outstanding  share of the Company's Common Stock,  $.01 par value per share
(the  "Common  Stock"),  to  stockholders  of record at the close of business on
October 20, 1986. Each Right entitles the registered holder to purchase from the
Company one one-hundredth of a share of Series A Junior Participating  Preferred
Stock, par value $.01 per share (the "Preferred  Stock"), at a Purchase Price of
$100 per one  one-hundredth  of a share of Preferred Stock  ("Purchase  Price"),
subject to  adjustment.  The  Purchase  Price may be paid,  at the option of the
holder, in cash or shares of Common Stock having a value at the time of exercise
equal to the Purchase  Price.  The  description  and terms of the Rights are set
forth in a Rights  Agreement,  renewed and  restated as of October 19, 1996 (the
"Rights Agreement"),  between the Company and The Bank of New York (as successor
to Morgan Shareholder Services Trust Company),  as Rights Agent, as subsequently
amended by an Amendment No. 1 to Rights Agreement dated as of August 6, 1999.

                  Initially,  the Rights will be represented by the certificates
evidencing  the  Common  Stock  and  no  separate  Right  Certificates  will  be
distributed.  Upon the earlier of the following dates (the "Distribution Date"),
except as permitted by the Amendment No. 1 to Rights Agreement,  the Rights will
separate from the Common Stock: (i) 10 days following a public announcement that
a person or group of affiliated or associated  persons (an  "Acquiring  Person")
has acquired,  or obtained the right to acquire,  beneficial ownership of 20% or
more of the outstanding shares of Common Stock (the "Stock  Acquisition  Date"),
(ii) 10 days following the commencement of, or first  announcement of the intent
of any person or persons to  commence,  a tender  offer or  exchange  offer that
would  result  in a  person  or  group  beneficially  owning  20% or more of the
outstanding  shares of Common  Stock,  or (iii) 10 days after a majority  of the
Continuing  Directors (as defined below) of the Company shall declare any person
to be an "Adverse Person," upon a determination that such person,  together with
its affiliates and associates,  has become the beneficial  owner of an amount of
Common  Stock  which a majority of the  Continuing  Directors  determines  to be
substantial  (but in no event less than 15% of the  shares of Common  Stock then
outstanding) and a determination by a majority of the Continuing  Directors that
(a) such beneficial ownership by such person is intended to cause the Company to
repurchase  the  Common  Stock  beneficially  owned by such  person  or to cause
pressure on the Company to take action or enter into a transaction  or series of
transactions  intended to provide  such person with  short-term  financial  gain
under circumstances where a majority of the Continuing Directors determines that
the best long-term  interests of the Company and its  stockholders  would not be
served by taking  such action or entering  into such  transactions  or series of
transactions  at that  time or (b)  such  beneficial  ownership  is  causing  or
reasonably likely to cause a material adverse impact  (including,  impairment of
relationships  with customers or impairment of the Company's ability to maintain
its competitive position) on the business or prospects of the Company.

                  Until the Distribution  Date, (i) the Rights will be evidenced
by the Common Stock certificates and will be transferred with and only with such
Common  Stock  certificates,  (ii) new Common  Stock  certificates  issued after
October 20, 1986 will contain a notation  incorporating  the Rights Agreement by
reference and (iii) the surrender  for transfer of any  certificates  for Common
Stock  outstanding  will also  constitute the transfer of the Rights  associated
with the Common Stock represented by such certificate.

                  The Rights are not exercisable until the Distribution Date and
will  expire at 5:00 P.M.  New York City time,  on October  19, 2001 (the "Final
Expiration Date"), unless earlier redeemed by the Company as described below.

                  As soon as  practicable  after the  Distribution  Date,  Right
Certificates  will be mailed to the holders of record of the Common  Stock as of
the close of business on the  Distribution  Date and,  thereafter,  the separate
Right Certificates alone will represent the Rights.  Only shares of Common Stock
issued prior to the Distribution Date will be issued with Rights.

                  In the event  that the Board of  Directors  determines  that a
person is an Adverse  Person or, at any time  following the  Distribution  Date,
except as permitted by the Amendment No. 1 to Rights Agreement,  (i) the Company
is the surviving  corporation in a merger or other business  combination with an
Acquiring Person and its Common Stock is not changed or exchanged, (ii) a Person
becomes the beneficial owner of more than 25% of the then outstanding  shares of
Common Stock (except  pursuant to an offer for all outstanding  shares of Common
Stock which a majority of the Continuing  Directors determines to be fair to and
otherwise in the best interests of the Company and its  stockholders),  (iii) an
Acquiring Person engages in one or more "self-dealing" transactions as set forth
in the  Rights  Agreement,  or (iv)  during  such time as there is an  Acquiring
Person,  an event  occurs which  results in such  Acquiring  Person's  ownership
interest  being  increased by more than 1% (e.g.,  a reverse stock split),  each
holder of a Right  promptly  thereafter  (but in the case of (ii) above,  5 days
thereafter) will have the right to receive, upon exercise,  Common Stock (or, in
certain circumstances, cash, property or other securities of the Company) having
a value equal to two times the exercise price of the Right.  Notwithstanding any
of the  foregoing,  following  the  occurrence of any of the events set forth in
this paragraph,  all Rights that are, or (under certain circumstances  specified
in the Rights Agreement) were,  beneficially owned by any Acquiring Person or an
Adverse  Person  will be null and  void.  However,  Rights  are not  exercisable
following the occurrence of any of the events set forth above until such time as
the Rights are no longer redeemable by the Company as set forth below.

                  For  example,  at an  exercise  price of $100 per Right,  each
Right not owned by an Acquiring Person (or by certain related parties) following
an event  set forth in the  preceding  paragraph  would  entitle  its  holder to
purchase $200 worth of Common Stock (or other consideration, as noted above) for
$100.  Assuming that the Common Stock had a per share value of $50 at such time,
the holder of each valid Right  would be  entitled  to  purchase  four shares of
Common Stock for $100.

                  Unless the Rights are earlier redeemed,  in the event that, at
any time  following  the Stock  Acquisition  Date,  except as  permitted  by the
Amendment No. 1 to Rights Agreement,  (i) the Company is acquired in a merger or
other business combination transaction in which the Company is not the surviving
corporation  (other than a merger which follows an offer described in the second
preceding  paragraph  and is at the  same  price),  or  (ii)  50% or more of the
Company's assets or earning power is sold or transferred, each holder of a Right
(except  rights  which  previously  have been voided as set forth  above)  shall
thereafter  have the right to receive,  upon  exercise of such  holder's  Right,
common  stock of the  acquiring  company  having a value  equal to two times the
exercise price of the Right.

                  The events set forth in the third preceding paragraph, and the
events set forth in subsections  (i) and (ii) of the first  preceding  paragraph
shall collectively be termed "Triggering Events" and each a "Triggering Event."

                  The   Purchase   Price   payable,   and  the   number  of  one
one-hundredths  of a share of Preferred  Stock or other  securities  or property
issuable,  upon  exercise of the Rights are subject to  adjustment  from time to
time  to  prevent  dilution  (i) in the  event  of a  stock  dividend  on,  or a
subdivision,  combination or  reclassification  of, the Preferred Stock, (ii) if
holders  of the  Preferred  Stock are  granted  certain  rights or  warrants  to
subscribe for Preferred Stock or convertible securities at less than the current
market price of the Preferred  Stock, or (iii) upon the  distribution to holders
of the Preferred Stock of evidences of indebtedness or assets (excluding regular
quarterly  cash  dividends) or of  subscription  rights or warrants  (other than
those referred to above).

                  With certain exceptions,  no adjustment in the Purchase Price
will  be required until cumulative  adjustments  amount  to at  least 1% of the
Purchase Price.

                  At any time on or prior to the close of  business on the tenth
day following the Stock  Acquisition  Date, the Company may redeem the Rights in
whole,  but not in part, at a price of $.01 per Right,  payable in cash or stock
(the "Redemption Price"). The Company may not redeem the Rights if a majority of
the  Continuing  Directors has  previously  determined a person to be an Adverse
Person.  After  the  redemption  period  has  expired,  the  Company's  right of
redemption  may be  reinstated  if an Acquiring  Person  reduces his  beneficial
ownership  to 10% or  less  of the  outstanding  shares  of  Common  Stock  in a
transaction  or series of  transactions  not involving the Company.  Immediately
upon the  action of the Board of  Directors  ordering  redemption  of the Rights
with, where required, the concurrence of a majority of the Continuing Directors,
the Rights will terminate and the only right of the holders of Rights will be to
receive the $.01 Redemption Price.

                  The shares of Preferred Stock purchasable upon exercise of the
Rights will have a minimum  preferential  quarterly dividend of $2.50 per share,
but will be entitled to receive,  in the aggregate,  a dividend of 100 times the
dividend  declared on the shares of Common Stock.  In the event of  liquidation,
the  holders of the shares of  Preferred  Stock  will be  entitled  to receive a
minimum  liquidation  payment of $100 per share, but will be entitled to receive
an aggregate  liquidation  payment equal to 100 times the payment made per share
of Common  Stock.  Each share of  Preferred  Stock will have one hundred  votes,
voting  together  with the shares of Common  Stock.  In the event of any merger,
consolidation  or  other  transaction  in  which  shares  of  Common  Stock  are
exchanged,  each share of Preferred  Stock will be entitled to receive 100 times
the amount and type of  consideration  received per share of Common  Stock.  The
rights of the shares of Preferred Stock as to dividends and liquidation,  and in
the event of mergers and consolidation, are protected by customary anti-dilution
provisions.

                  The term "Continuing  Directors" means any member of the Board
of  Directors  of the Company who was a member of the Board prior to the date of
the Rights Agreement, and any person who is subsequently elected to the Board if
such  person  is  recommended  or  approved  by a  majority  of  the  Continuing
Directors, but shall not include an Acquiring Person or an Adverse Person, or an
affiliate  or  associate of an  Acquiring  Person or an Adverse  Person,  or any
representative of the foregoing entities.

                  Until a Right is exercised,  the holder thereof, as such, will
have no rights as a stockholder of the Company, other than rights resulting from
such  holder's  ownership  of  shares  of  Common  Stock,   including,   without
limitation, the right to vote or to receive dividends. While the distribution of
the Rights will not be taxable to stockholders  or to the Company,  stockholders
may,  depending upon the  circumstances,  recognize  taxable income in the event
that the Rights become exercisable for Common Stock (or other  consideration) of
the Company or for common stock of the acquiring company as set forth above.

                  In  general,  other  than  those  provisions  relating  to the
principal  economic terms of the Rights,  the provisions of the Rights Agreement
may  be  amended  by  the  Board  of  Directors  of  the  Company  prior  to the
Distribution  Date.  After the  Distribution  Date, the provisions of the Rights
Agreement may be amended by the Board (with the concurrence of a majority of the
Continuing  Directors) in order to cure any ambiguity,  to make changes which do
not adversely affect the interests of holders of Rights (excluding the interests
of any  Acquiring  Person),  or to shorten or lengthen any time period under the
Rights Agreement; provided, however, that no amendment to adjust the time period
governing  redemption  shall  be  made  at  such  time  as the  Rights  are  not
redeemable.

                  A copy of the  Rights  Agreement  and the  Amendment  No. 1 to
Rights Agreement have been filed with the Securities and Exchange  Commission as
Exhibits  to  Registration  Statements  on  Form  8-A/A.  A copy  of the  Rights
Agreement and Amendment  No. 1 to Rights  Agreement is available  free of charge
from the Company.  This summary description of the Rights does not purport to be
complete and is  qualified in its entirety by reference to the Rights  Agreement
and the Amendment No. 1 to Rights  Agreement,  which are incorporated  herein by
reference.



Item 2.  Exhibits

Exhibit 1.        "Renewed   and   Restated   Rights  Agreement",  dated  as  of
                  October 16, 1996, by and between Data General  Corporation and
                  The Bank of New York as Rights Agent,  which includes the form
                  of Certificate of Designations  setting forth the terms of the
                  Series A Junior  Participating  Cumulative  Preferred Stock as
                  Exhibit A, the form of Right  Certificate as Exhibit B and the
                  Summary of Rights to Purchase  Preferred  Shares as Exhibit C,
                  filed as Exhibit 1 to that Form 8-A/A  filed June 27, 1996 and
                  incorporated herein by reference.


Exhibit 2.        "Amendment No. 1 to Rights  Agreement"  dated  as of August 6,
                  1999 between  Data General  Corporation  and  The Bank of New
                  York as Rights Agent.


Exhibit 3.        Agreement  and  Plan  of Merger  dated as of August 6, 1999 by
                  and among EMC Corporation, Emerald Merger Corporation and Data
                  General  Corporation,  filed as  Exhibit  2.1 to that Form 8-K
                  filed August 11, 1999 and  incorporated  herein  by reference.

Exhibit 4.        Stock  Option  Agreement  dated  as of  August  6, 1999 by and
                  between EMC Corporation and Data General Corporation, filed as
                  Exhibit  2.2 to that  Form  8-K  filed  August  11,  1999  and
                  incorporated herein by reference.





                                    SIGNATURE


         Pursuant to the  requirements of Section 12 of the Securities  Exchange
Act of 1934, the Registrant  has duly caused this  Registration  Statement to be
signed on its behalf by the undersigned, thereto duly authorized.


                                                     DATA GENERAL CORPORATION




                                                     By:      /s/ Jacob Frank
                                                             ------------------
                                                                Jacob Frank
                                                             Vice President and
                                                              General Counsel


Dated: September 13, 1999

EX-2

Exhibit 2


                       AMENDMENT NO. 1 TO RIGHTS AGREEMENT


This AMENDMENT NO. 1, dated as of August 6, 1999 (this "Amendment"),  is between
Data General Corporation,  a Delaware  corporation (the "Corporation"),  and The
Bank of New York, as Rights Agent (the "Rights Agent").


                                    Recitals


WHEREAS, the Corporation and the Rights Agent are parties to a Rights Agreement,
dated  as  of  October  3,  1986   (Renewed and Restated as of October 19, 1996)
(the "Rights Agreement"); and


WHEREAS,  EMC  Corporation,   a  Massachusetts   corporation  ("EMC"),  and  the
Corporation  propose to enter into an Agreement  and Plan of Merger (the "Merger
Agreement")  pursuant to which the  Corporation  will merge with Emerald  Merger
Corporation,  a Delaware corporation and subsidiary of EMC (the "Merger"), and a
related Stock Option  Agreement by and between the Corporation,  as issuer,  and
EMC,  as  grantee  (the  "Option  Agreement").  The  Board of  Directors  of the
Corporation  has  approved  the  Merger  Agreement,  the  Merger  and the Option
Agreement; and


WHEREAS,  pursuant to Section 26 of the Rights Agreement, the Board of Directors
of the Corporation  has determined that an amendment to the Rights  Agreement as
set forth herein is necessary and desirable in connection with the foregoing and
the  Corporation  and the Rights  Agent  desire to evidence  such  amendment  in
writing;


NOW, THEREFORE,  in consideration of the foregoing and the mutual agreements set
forth herein, the parties hereto agree as follows:


(a) Amendment of Section 1(a).  Section 1(a) of the Rights  Agreement is amended
to add the following sentence at the end thereof:


         Notwithstanding  anything in this Rights Agreement to the contrary, EMC
         shall  not be  deemed  to be an  Acquiring  Person by virtue of (i) the
         consummation  of the Merger,  (ii) the  execution  and  delivery of the
         Merger Agreement and the Option Agreement, or (iii) the consummation of
         any of the other transactions  contemplated in the Merger Agreement and
         the Option Agreement.


(b)  Amendment  of  Section   3(a).  Section 3 (a)  of  the  Rights Agreement is
amended to add the following sentence at the end thereof:


         Notwithstanding  anything in this Rights  Agreement to the contrary,  a
         Distribution Date shall not be deemed to have occurred as the result of
         (i) the  consummation  of the Merger,  (ii) the execution of the Merger
         Agreement and the Option Agreement, or (iii) the consummation of any of
         the other  transactions  contemplated  in the Merger  Agreement and the
         Option Agreement.


(c) Amendment of Section 1(k).  Section 1(k) of the Rights  Agreement is amended
and restated to read as follows:


                  (i)   "Final Expiration Date" shall mean October 19, 2001.


                  (ii)  "Merger"  shall have the meaning set forth in the Merger
                        Agreement.


                  (iii) "Merger Agreement" shall mean that certain Agreement and
                        Plan of Merger, dated as of August 6, 1999, by and among
                        EMC, Emerald Merger Corporation and the Corporation,  as
                        amended from time to time.


                  (iv)  "Option  Agreement" shall mean that certain Stock Option
                        Agreement,  dated as of August 6, 1999,  by and  between
                        EMC,  as grantee,  and the  Corporation,  as issuer,  as
                        amended from time to time.


                  (v)  "EMC"  shall  mean  EMC   Corporation,   a  Massachusetts
                       corporation.


(d)  Amendment of Section 7(a).  Section 7(a) of the Rights  Agreement is hereby
amended and restated to state in its entirety as follows:


         Subject to Section  7(e)  hereof,  the  registered  holder of any Right
         Certificate  may  exercise  the  Rights  evidenced  thereby  (except as
         otherwise  provided  herein)  in whole or in part at any time after the
         Distribution  Date upon  surrender of the Right  Certificate,  with the
         form of election to purchase on the reverse side thereof duly executed,
         to the Rights Agent at the principal  office of the Rights Agent as set
         forth in Section 25 hereof, together with payment of the Purchase Price
         with respect to each one one-hundredth of a share of Preferred Stock as
         to which the Rights are exercised, at or prior to the Close of business
         on the earlier of (i) the Final Expiration Date, (ii) the date on which
         the Rights are redeemed as provided in Section 23 hereof,  or (iii) the
         consummation  of the Merger (such earlier date being herein referred to
         as the "Expiration Date").


(e)  Amendment of Section 12.  Section 12 of  the Rights Agreement is amended to
add the following sentence at the end thereof:


         Notwithstanding anything in this Rights Agreement to the contrary, none
         of (i) the consummation of the Merger, (ii) the execution of the Merger
         Agreement and the Option  Agreement,  and (iii) the consummation of any
         of the other transactions  contemplated in the Merger Agreement and the
         Option  Agreement shall be deemed to be events of the type described in
         the first  sentence of this  Section 12, and shall not cause the Rights
         to be adjusted or exercisable  in accordance  with, or any other action
         to be taken or obligation to arise pursuant to, this Section 12.


(f) Effectiveness. This Amendment shall be deemed effective as of the date first
written above, as if executed on such date. Except as amended hereby, the Rights
Agreement  shall  remain  in full  force  and  effect  and  shall  be  otherwise
unaffected hereby.


(g)  Miscellaneous.  This Amendment  shall be deemed to be a contract made under
the laws of the State of Delaware and for all purposes  shall be governed by and
construed in accordance  with the laws of such state  applicable to contracts to
be made and performed  entirely  within such state,  except as to the duties and
liabilities  of the Rights  Agent which shall be  governed by and  construed  in
accordance  with  the laws of the  State  of New  York.  This  Amendment  may be
executed in any number of counterparts,  each of such counterparts shall for all
purposes be deemed to be an original,  and all such counterparts  shall together
constitute but one and the same instrument. If any term, provision,  covenant or
restriction  of this Amendment is held by a court of competent  jurisdiction  or
other  authority  to be invalid,  void or  unenforceable,  the  remainder of the
terms, provisions,  covenants and restrictions of this Amendment shall remain in
full force and effect and shall in no way be affected,  impaired or invalidated.
It is the intent of the parties  hereto to enforce the  remainder  of the terms,
provisions, covenants and restrictions to the maximum extent permitted by law.




                  IN  WITNESS  WHEREOF,  the  parties hereto  have  caused  this
Amendment No. 1 to  be  duly executed,  all as of  the date and year first above
written.





Attest:                                                 DATA GENERAL CORPORATION

By:      /s/ James K. Jacobs                      By:      /s/ Robert C. McBride
   -------------------------                         ---------------------------
Name:    James K. Jacobs                          Name:    Robert C. McBride
Title:   Assistant Secretary                      Title:   Chief Administrative
                                                  Officer, Treasurer  and  Vice
                                                  President


Attest:                                                 THE BANK OF NEW YORK,
                                                        AS RIGHTS AGENT

By:      /s/ Ralph Chianese                       By:      /s/ Eon A. Canzius
   -------------------------                         ---------------------------
Name:    Ralph Chianese                           Name:    Eon A. Canzius
Title:   Vice President                           Title:   Assistant Treasurer