Exhibit 8.1

          [Letterhead of Skadden, Arps, Slate, Meagher & Flom LLP]


                                         October 12, 1999


EMC Corporation
35 Parkwood Drive
Hopkinton, MA 01748


Ladies and Gentlemen:

            We have acted as tax counsel to EMC Corporation ("EMC"), a
Massachusetts corporation, in connection with (i) the Merger, as defined
and described in the Agreement and Plan of Merger, dated as of August 6,
1999 (the "Merger Agreement"), by and among EMC, Emerald Merger
Corporation, a Delaware corporation and a wholly owned subsidiary of EMC
("Merger Sub") and Data General Corporation, a Delaware corporation ("Data
General"), and (ii) the preparation and filing of the Registration
Statement with the Securities and Exchange Commission (the "Commission")
under the Securities Act of 1933, as amended (the "Securities Act"), on
September 7, 1999 (the "Registration Statement"), which includes the Proxy
Statement/Prospectus of Data General (the "Proxy Statement/Prospectus").
The delivery of this opinion, dated as of October 12, 1999, is a condition
of the Merger pursuant to Section 7.1(e) of the Merger Agreement. Unless
otherwise indicated, each capitalized term used herein has the meaning
ascribed to it in the Merger Agreement.

            In connection with this opinion, we have examined the Merger
Agreement, the Proxy Statement/Prospectus and such other documents and
corporate records as we have deemed necessary or appropriate in order to
enable us to render the opinion below. For purposes of this opinion, we
have assumed (i) the validity and accuracy of the documents and corporate
records that we have examined and the facts and representations concerning
the Merger that have come to our attention during our engagement, (ii) that
the Merger will be consummated in the manner described in the Merger
Agreement and the Proxy Statement/Prospectus, (iii) that the
representations made to us by EMC and Data General in their respective
certificates dated as of the date hereof, and delivered to us for purposes
of this opinion, are accurate and complete, (iv) that the Merger will be
reported by EMC, Merger Sub and Data General on their respective federal
income tax returns in a manner consistent with the opinion set forth below,
and (v) that each of the Merger and the Upstream Merger, if it occurs, will
qualify as a statutory merger under the applicable laws of the State of
Delaware and the Commonwealth of Massachusetts.

            In rendering our opinion, we have considered the applicable
provisions of the Code, Treasury Department regulations promulgated
thereunder, pertinent judicial authorities, interpretive rulings of the IRS
and such other authorities as we have considered relevant. It should be
noted that statutes, regulations, judicial decisions and administrative
interpretations are subject to change at any time (possibly with
retroactive effect). A change in the authorities or the accuracy or
completeness of any of the facts, information, documents, corporate
records, covenants, statements, representations or assumptions on which our
opinion is based could affect our conclusions. This opinion is expressed as
of the date hereof, and we are under no obligation to supplement or revise
our opinion to reflect any changes (including changes that have retroactive
effect) (i) in applicable law or (ii) in any fact, information, document,
corporate record, covenant, statement, representation or assumption stated
herein that becomes untrue or incorrect.

            Subject to the assumptions set forth above, and the assumptions
and qualifications set forth in the discussion in the Proxy
Statement/Prospectus under the heading "United States Federal Income Tax
Consequences of the Merger" (the "Discussion"), in our opinion the Merger
will qualify, either alone or taken together with the Upstream Merger, as a
reorganization within the meaning of Section 368(a) of the Code. The
opinion set forth above does not address all of the United States federal
income tax consequences of the Merger. In addition, we express no opinion
as to the United States federal, state, local, foreign or other tax
consequences other than as set forth above. Further, there can be no
assurances that the opinion expressed herein will be accepted by the
Internal Revenue Service (the "IRS") or, if challenged, by a court.

            This letter is furnished to you for use in connection with the
Merger, as described in the Merger Agreement and the Proxy
Statement/Prospectus, and is not to be used, circulated, quoted, or
otherwise referred to for any other purpose without our express written
permission.

                                 Very truly yours,


                                 /s/ Skadden, Arps, Slate, Meagher & Flom LLP