EXHIBIT 5.1

                                PERKINS COIE LLP

          1201 THIRD AVENUE, 48TH FLOOR, SEATTLE, WASHINGTON 98101-3099
                       TELEPHONE: 206 583-8888 FACSIMILE: 206 583-8500



                                  May 17, 2002



Advanced Digital Information Corporation
P.O. Box 97057
11431 Willows Road N.E.
Redmond, WA  98073-9757


        Re:    Registration Statement on Form S-8

Ladies and Gentlemen:

        We have acted as counsel to you in connection with the preparation of a
Registration Statement on Form S-8 (the "Registration Statement") under the
Securities Act of 1933, as amended ("the Act"), which you are filing with the
Securities and Exchange Commission with respect to up to 2,000,000 shares of
Common Stock, no par value (the "Shares"), as may be issued pursuant to the
Advanced Digital Information Corporation Amended and Restated 1999 Stock
Incentive Compensation Plan (the "Plan").

        We have examined the Registration Statement and such documents and
records of Advanced Digital Information Corporation and other documents as we
have deemed necessary for the purpose of this opinion. In giving this opinion,
we are assuming the authenticity of all instruments presented to us as
originals, the conformity with originals of all instruments presented to us as
copies and the genuineness of all signatures.

        Based upon and subject to the foregoing, we are of the opinion that any
original issuance Shares that may be issued pursuant to the Plan have been duly
authorized and that, upon the due execution by Advanced Digital Information
Corporation and the registration by its registrar of such Shares and the sale
thereof by Advanced Digital Information Corporation in accordance with the terms
of the Plan, and the receipt of consideration therefor in accordance with the
terms of the Plan, such 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. In giving such consent, we do not admit that we are in
the category of persons whose consent is required under Section 7 of the Act.

                                            Very truly yours,

                                            /S/ PERKINS COIE LLP