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                                                                     EXHIBIT 8.1


                                November 8, 2000


The Santa Cruz Operation
425 Encinal
Santa Cruz, CA  95061

         RE:  AGREEMENT AND PLAN OF REORGANIZATION BY AND AMONG CALDERA
              SYSTEMS, INC., A DELAWARE CORPORATION, ("CALDERA"); CALDERA
              HOLDING, INC., A DELAWARE CORPORATION, ("NEWCO") AND THE
              SANTA CRUZ OPERATION, INC., A CALIFORNIA CORPORATION ("SCO")

Ladies and Gentlemen:

         We have acted as counsel to SCO in connection with the proposed
transfer of certain assets from SCO to Newco in exchange for Newco stock and
cash and the proposed merger of a transitory merger subsidiary wholly-owned by
Newco ("Merger Sub"), with and into Caldera (collectively, the "Combination")
pursuant to an Agreement and Plan of Reorganization dated as of August 1, 2000
and amended as of September 13, 2000 (the "Agreement"). The Combination and
certain proposed transactions incident thereto are described in the Registration
Statement on Form S-4 (the "Registration Statement") of Newco which includes the
Proxy Statement/Prospectus of Caldera and SCO (the "Proxy
Statement/Prospectus"). This opinion is being rendered pursuant to the
requirements of Item 21(a) of Form S-4 under the Securities Act of 1933, as
amended. Unless otherwise indicated, any capitalized terms used herein and not
otherwise defined have the meaning ascribed to them in the Proxy
Statement/Prospectus.

         In connection with this opinion, we have examined and are familiar with
the Agreement, the Registration Statement, and such other presently existing
documents, records and matters of law as we have deemed necessary or appropriate
for purposes of our opinion. In addition, we have assumed (i) that the
Combination will be consummated in the manner contemplated by the Proxy
Statement/Prospectus and in accordance with the provisions of the Agreement;
(ii) the truth and accuracy of the representations and warranties made in the
Agreement by SCO, Newco, Caldera and Merger Sub; and (iii) the truth and
accuracy in all material respects of the certificates of representations to be
provided to us by SCO, Newco, Caldera, and Merger Sub.

         Because this opinion is being delivered prior to the Effective Time of
the Combination it must be considered prospective and dependent on future
events. There can be no assurance that changes in the law will not take place
which could affect the United States Federal income tax consequences of the
Combination or that contrary positions may not be taken by the Internal Revenue
Service.


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The Santa Cruz Operation
November 8, 2000
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         Based upon and subject to the foregoing, in our opinion, the discussion
contained in the Registration Statement under the caption "Material United
States Federal Income Tax Consequences of the Combination - Material Federal
Income Tax Consequences of the Combination to SCO," subject to the limitations
and qualifications described therein, sets forth the material United States
federal income tax consequences generally applicable to the SCO shareholders as
a result of the Combination.

         This opinion is furnished to you solely for use in connection with the
Registration Statement. We hereby consent to the filing of this opinion as an
Exhibit to the Registration Statement. We also consent to the reference to our
firm name wherever appearing in the Registration Statement with respect to the
discussion of the material federal income tax consequences of the Combination,
including the Proxy Statement/Prospectus constituting a part thereof, and any
amendment thereto. In giving this consent, we do not thereby admit that we in
the category of persons whose consent is required under Section 7 of the
Securities Act of 1933, as amended, or the rules and regulations of the
Securities and Exchange Commission thereunder, nor do we thereby admit that we
are experts with respect to any part of such Registration Statement within the
meaning of the term "experts" as used in the Securities Act of 1933, as amended,
or the rules and regulations of the Securities and Exchange Commission
thereunder.

                                    Very truly yours,


                                    WILSON SONSINI GOODRICH & ROSATI
                                    Professional Corporation