EXHIBIT 5.1


                                        
                                    November 28, 1995      



EMC Corporation
171 South Street
Hopkinton, Massachusetts  01748

               Re:  Registration of up to 17,500,000 Shares of the
                    Common Stock of EMC Corporation
                    -------------------------------------------------

Ladies and Gentlemen:

        We have acted as special counsel to EMC Corporation, a Massachusetts
corporation (the "Company"), in connection with the preparation of a
Registration Statement on Form S-4 (33-63993), as filed by the Company with
the Securities and Exchange Commission (the "Commission") on November 3, 1995 
and Amendment No. 1 thereto filed with the Commission on the date hereof
(as so amended, the "Registration Statement"). The Registration Statement
relates to the registration by the Company under the Securities Act of 1933, as
amended (the "1933 Act"), of up to 17,500,000 shares (the "Shares") of common
stock, $.01 par value per share, of the Company (the "Common Stock").

        In this connection, we have examined and are familiar with originals   
or copies, certified or otherwise identified to our satisfaction, of the       
Registration Statement; the Restated Articles of Organization of the Company,  
as amended, and the Amended and Restated Bylaws of the Company, each as in     
effect on the date hereof; certain resolutions adopted by the Board of         
Directors of the Company relating to the preparation and filing of the         
Registration Statement, the issuance of the Shares by the Company and certain
related matters; the Agreement and Plan of Merger dated as of October 25, 1995
(the "Merger Agreement") by and among the Company, EMC Merger Corporation 1995,
a Delaware corporation and a wholly owned subsidiary of the Company, and McDATA
Corporation, a Delaware corporation; certain other agreements, certificates of
public officials, certificates of officers or representatives of the Company and
others; a form of specimen certificate for the Common Stock; and such other
documents, certificates and records as we have deemed necessary or appropriate
as a basis for the opinion set forth herein. In our examination, we have assumed
the genuineness of all signatures, the legal capacity of natural persons, the
authenticity of all documents submitted to us as originals, the conformity to
original documents of all documents submitted to us as certified, conformed or
photostatic copies and the authenticity of the originals of such copies. As to
any facts material to the opinion expressed herein which we have not
independently established or verified, we have relied upon statements and
representations of officers and other representatives of the Company and others.

        Members of our firm are admitted to the Bar of the Commonwealth of
Massachusetts, and we express no opinion as to the laws of any other  
jurisdiction.                                                          

        Based upon and subject to the foregoing, we are of the opinion that when
(i) issued in accordance with the Merger Agreement and the resolutions of the
Board of Directors of the Company relating thereto and (ii) certificates
representing the Shares in the form of the specimen certificate for the Common
Stock examined by us have been manually signed by an authorized officer of the
transfer agent and registrar for the Common Stock and registered by such
transfer agent and registrar, the Shares will be validly issued, fully paid and
nonassessable.

 
        We hereby consent to the filing of this opinion as an exhibit to the    
Registration Statement and to the reference to this firm under the caption      
"Legal Matters" in the Consent Solicitation/Prospectus filed as part of the     
Registration Statement.  In giving such consent, we do not thereby admit that   
we are in the category of persons whose consent is required under Section 7 of  
the 1933 Act or the rules and regulations of the Commission promulgated         
thereunder.                                                                     
                                                                                
        This opinion is furnished by us, as your counsel, in connection with    
the filing of the Registration Statement and, except as provided in the         
immediately preceding paragraph, is not to be used, circulated, quoted for any  
other purpose or otherwise referred to or relied upon by any other person       
without our express written permission.



                                       Very truly yours,

                                           
                                       SKADDEN, ARPS, SLATE, MEAGHER & FLOM