EXHIBIT 8.1

                                                       
                                                   November 28, 1995      



  EMC Corporation
  171 South Street
  Hopkinton, Massachusetts 01748

  Ladies and Gentlemen:

          You have requested our opinion regarding the discussions of the
  material U.S. federal income tax consequences under the captions "SUMMARY--The
  Merger--Certain Federal Income Tax Consequences" and "THE MERGER--Certain
  Federal Income Tax Consequences" in the Consent Solicitation/Prospectus (the
  "Consent Solicitation/Prospectus") which will be included in Amendment No. 1
  to the Registration Statement on Form S-4 (33-63993) (the "Registration
  Statement") filed on the date hereof with the Securities and Exchange
  Commission (the "Commission") under the Securities Act of 1933, as amended
  (the "Securities Act"). The Consent Solicitation/Prospectus relates to the
  proposed merger of EMC Merger Corporation 1995, a wholly owned subsidiary of
  EMC Corporation, with and into McDATA Corporation. This opinion is delivered
  in accordance with the requirements of Item 601(b)(8) of Regulation S-K under
  the Securities Act.

          In rendering our opinion, we have reviewed the Consent
  Solicitation/Prospectus and such other materials as we have deemed necessary
  or appropriate as a basis for our opinion.  In addition, we have considered
  the applicable provisions of the Internal Revenue Code of 1986, as amended,
  Treasury regulations, pertinent judicial authorities, rulings of the Internal
  Revenue Service, and such other authorities as we have considered relevant.

          Based upon the foregoing, it is our opinion that the statements made
  under the captions "SUMMARY--The Merger--Certain Federal Income Tax
  Consequences" and "THE MERGER--Certain Federal Income Tax Consequences" in the
  Consent Solicitation/Prospectus, to the extent that they constitute matters of
  law or legal conclusions, are correct in all material respects.  There can be
  no assurance that contrary positions may not be asserted by the Internal
  Revenue Service.

          This opinion is being furnished in connection with the Consent
  Solicitation/Prospectus.  You may rely upon and refer to the foregoing opinion
  in the Consent Solicitation/Prospectus.  Any variation or difference in the
  facts from those set forth or assumed either herein or in the Consent
  Solicitation/Prospectus may affect the conclusions stated herein.

          In accordance with the requirements of Item 601(b)(23) of Regulation
  S-K under the Securities Act, we hereby consent to the use of our name under
  the captions "SUMMARY--The Merger--Certain Federal Income Tax Consequences"
  and "THE MERGER--Certain Federal Income Tax Consequences" in the Consent
  Solicitation/Prospectus and to the filing of this opinion as an Exhibit to the
  Registration Statement.  In giving this consent, we do not admit that we come
  within the category of persons whose consent is required under Section 7 of
  the Securities Act or the rules and regulations of the Commission thereunder.


                                       Very truly yours,

                                           
                                       SKADDEN, ARPS, SLATE, MEAGHER & FLOM