EXHIBIT 99.1

  October 25, 1995



  Members of the Board of Directors

  McDATA Corporation
  310 Interlocken Parkway
  Broomfield, CO  80021-3464

  Gentlemen:

       We understand that McDATA Corporation, a Delaware corporation (the
  "Company"), EMC Corporation, a Massachusetts corporation ("Acquiror"), and EMC
  Merger Corporation 1995, a Delaware corporation and wholly-owned subsidiary of
  Acquiror ("Sub"), propose to enter into an Agreement and Plan of Merger dated
  as of October 25, 1995 (the "Merger Agreement"), pursuant to which Sub will be
  merged with and into the Company, which will be the surviving entity (the
  "Merger").  Pursuant to the Merger, as more fully described in the Merger
  Agreement, we understand that the outstanding shares of the common stock of
  the Company, $.001 par value per share (the "Company Common Stock"), not held
  as treasury stock by the Company or owned directly or indirectly by Acquiror,
  will be converted into an aggregate number of shares of the common stock of
  Acquiror, $.01 par value per share (the "Acquiror Common Stock"), equal to the
  quotient of (i) $180,000,000 plus the Net Quick Assets Amount (as defined in
  the Merger Agreement) divided by (ii) the average per share closing price of
  the Acquiror Common Stock as reported on the New York Stock Exchange over the
  ten (10) trading days immediately preceding the closing date of the Merger
  (the "Consideration").  Up to ten percent (10%) of the Consideration is
  subject to cancellation to cover potential indemnification claims of Acquiror
  under the Merger Agreement for breaches of the representations, warranties and
  covenants of the Company contained therein ("Indemnification Claims").

       You have asked for our opinion as to whether the Consideration to be
  received by the stockholders of the Company pursuant to the Merger is fair to
  such stockholders from a financial point of view, as of the date hereof.

       In connection with our opinion, we have, among other things:  (i)
  reviewed certain publicly available financial and other data with respect to
  Acquiror, and certain financial and other data with respect to the Company
  provided to us by its management, including the consolidated financial
  statements for recent years and interim periods to July 1, 1995, in the case
  of Acquiror, and September 29, 1995, in the case of the Company, and certain
  other relevant financial and operating data relating to Acquiror and the
  Company made available to us from published sources, in the case of Acquiror,
  and from the internal records of the Company and Acquiror; (ii) reviewed a
  draft dated October 20, 1995 of the Merger Agreement provided to us by the
  Company; (iii) reviewed certain historical market prices and trading volumes
  of the Acquiror Common Stock as reported on the New York Stock Exchange; (iv)
  compared the Company and Acquiror from a financial point of view with certain
  other companies in the networking and storage computer industries that we
  deemed to be relevant; (v) considered the financial terms, to the extent
  publicly available, of selected recent business combinations of companies in
  the networking and storage computer industries that we deemed to be
  comparable, in whole or in part, to the Merger; (vi) reviewed and discussed
  with representatives of the management of the Company and Acquiror certain
  information of a business and financial nature regarding the Company

 
  and Acquiror, furnished to us by them, including financial forecasts and
  related assumptions of the Company and Acquiror; (vii) made inquiries
  regarding and discussed the Merger and the draft of the Merger Agreement and
  other matters related thereto with the Company's counsel; and (viii) performed
  such other analyses and examinations as we have deemed appropriate.

       In connection with our review, we have assumed and relied upon the
  accuracy and completeness of the foregoing information and we have not assumed
  any responsibility for independent verification of such information.  With
  respect to the financial forecasts for the Company and Acquiror provided to us
  by their respective managements, we have assumed for purposes of our opinion
  that the forecasts have been reasonably prepared on bases reflecting the best
  available estimates and judgments of their respective managements at the time
  of preparation as to the future financial performance of the Company and
  Acquiror (including, in the case of the Company, the estimates and judgments
  of its management relating to the Company's relationship with IBM that are
  reflected in such forecasts) and that they provide a reasonable basis upon
  which we can form our opinion.  With respect to the forecasts for the Company
  provided to us by its management, for purposes of our analyses, we have
  projected future financial performance of the Company for a period of two
  years beyond its management's forecast period.  In preparing such projections,
  we have used assumptions more conservative than those used by the Company's
  management in preparing its projections.  We have discussed the adjusted
  forecasts and related assumptions with management of the Company and they have
  acknowledged our use of such adjusted forecasts and assumptions in arriving at
  our opinion.  We have also assumed that there have been no material changes in
  the Company's or Acquiror's assets, financial condition, results of
  operations, business or prospects since the respective dates of their last
  financial statements made available to us and that there will be no
  Indemnification Claims.  We have relied on advice of counsel and independent
  accountants to the Company as to all legal and financial reporting matters
  with respect to the Company, the Merger and the draft of the Merger Agreement.
  We have assumed that the Merger will be consummated in a manner that complies
  in all respects with the applicable provisions of the Securities Act of 1933,
  as amended (the "Securities Act"), the Securities Exchange Act of 1934, as
  amended, and all other applicable federal and state statutes, rules and
  regulations.  In addition, we have not assumed responsibility for making an
  independent evaluation, appraisal or physical inspection of the assets or
  individual properties of the Company or Acquiror, nor have we been furnished
  with any such appraisals.  Finally, our opinion is based on economic, monetary
  and market and other conditions as in effect on, and the information made
  available to us as of, the date hereof.

       We have further assumed, with your consent, that the Merger will be
  consummated in accordance with the terms described in the draft of the Merger
  Agreement without any amendments thereto, and without wavier by the Company or
  Acquiror of any of the conditions to their respective obligations thereunder.

       In the ordinary course of our business, we actively trade the equity
  securities of Acquiror for our own account and for the accounts of customers
  and, accordingly, may at any time hold a long or short position in such
  securities.

       Based upon the foregoing and in reliance thereon, it is our opinion that
  the Consideration to be received by the stockholders of the Company pursuant
  to the Merger is fair to such stockholders from a financial point of view, as
  of the date hereof.

       This opinion is furnished pursuant to our engagement letter, dated
  February 14, 1995.  This opinion is addressed to the Board of Directors of the
  Company only and is not intended to be and shall not be deemed to be a
  recommendation to any stockholder as to how such stockholder should vote with
  respect to the Merger.  This opinion may not be used or referred to by the
  Company, or quoted or

 
  disclosed to any person in any manner, without our prior written consent.  In
  furnishing this opinion, we do not admit that we are experts within the
  meaning of the term "experts" as used in the Securities Act and the rules and
  regulations promulgated thereunder, nor do we admit that this opinion
  constitutes a report or valuation within the meaning of Section 11 of the
  Securities Act.

                                       Very truly yours,



                                       MONTGOMERY SECURITIES