EXHIBIT 8.1
 
   
                                 March 7, 1997
    
 
Centura Software Corporation
1060 Marsh Road
Menlo Park, CA 94025
 
Ladies and Gentlemen:
 
    This opinion is being delivered to you pursuant to Section 6.1(h) of the
Agreement and Plan of Reorganization (the "Agreement") among Centura Software
Corporation, a California corporation ("Centura"), its wholly owned subsidiary,
IS Acquisition Corporation, a Delaware corporation ("Sub"), InfoSpinner, Inc., a
Delaware corporation ("InfoSpinner"), dated as of January 6, 1997. Pursuant to
the Agreement and the related Agreement of Merger (collectively, the "Merger
Agreements"), Sub will merge with and into InfoSpinner (the "Merger"), and
InfoSpinner will become a wholly owned subsidiary of Centura.
 
    Except as otherwise provided, capitalized terms referred to herein have the
meanings set forth in the Merger Agreements. All section references, unless
otherwise indicated, are to the Internal Revenue Code of 1986, as amended (the
"Code").
 
    We have acted as legal counsel to Centura and Sub in connection with the
Merger. As such, and for the purpose of rendering this opinion, we have examined
(or will examine on or prior to the Effective Time) and are relying (or will
rely) upon (without any independent investigation or review thereof) the truth
and accuracy, at all relevant times, of the statements, covenants,
representations and warranties contained in the following documents (including
all schedules and exhibits thereto):
 
        1.  The Merger Agreements (including Exhibits);
 
   
        2.  Representations made (or to be made prior to the Effective Time) to
    us by Centura and Sub in a letter reproduced as Exhibit A hereto;
    
 
   
        3.  Representations made (or to be made prior to the Effective Time) to
    us by InfoSpinner in a letter reproduced as Exhibit B hereto;
    
 
   
        4.  Representations made (or to be made prior to the Effective Time) to
    us by certain stockholders of InfoSpinner in the Affiliates Agreements and
    the Continuity of Interest Certificates;
    
 
        5.  An opinion of counsel, received by InfoSpinner from Gunderson
    Dettmer Stough Villeneuve Franklin & Hachigian, LLP identical in form and
    substance to this opinion (the "GDSVF&H Tax Opinion");
 
        6.  The Centura Information Statement relating to the Merger; and
 
        7.  Such other instruments and documents related to the formation,
    organization and operation of Centura, InfoSpinner and Sub or to the
    consummation of the Merger and the transactions contemplated thereby as we
    have deemed necessary or appropriate.
 
    In connection with rendering this opinion, we have assumed or obtained
representations (and are relying thereon, without any independent investigation
or review thereof) that:
 
        A. Original documents (including signatures) are authentic, documents
    submitted to us as copies conform to the original documents, and there has
    been (or will be by the Effective Time) due execution and delivery of all
    documents where due execution and delivery are prerequisites to
    effectiveness thereof;

        B.  Any representation or statement made "to the best knowledge of" or
    otherwise similarly qualified is correct without such qualification. As to
    all matters in which a person or entity making a representation has
    represented that such person or entity either is not a party to, does not
    have, or is not aware of any plan, intention, understanding or agreement to
    take an action, there is in fact no plan, intention, understanding or
    agreement and such action will not be taken;
 
        C.  The Merger will be consummated pursuant to the Merger Agreements and
    will be effective under the laws of the states of Delaware and California;
 
        D. The stockholders of InfoSpinner do not, and will not on or before the
    Effective Time, have an existing plan or intent to dispose of an amount of
    Centura Common Stock to be received in the Merger (or to dispose of
    InfoSpinner capital stock in anticipation of the Merger) such that the
    stockholders of InfoSpinner will not receive and retain a meaningful
    continuing equity ownership in Centura that is sufficient to satisfy the
    continuity of interest requirement as specified in Treas. Reg.
    Section1.368-1(b) and as interpreted in certain Internal Revenue Service
    rulings and federal judicial decisions;
 
        E.  After the Merger, InfoSpinner will hold "substantially all" of its
    and Sub's properties within the meaning of Section 368(a)(2)(E)(i) of the
    Code and the regulations promulgated thereunder and will continue its
    historic business or use a significant portion of its historic business
    assets in a business;
 
        F.  To the extent any expenses relating to the Merger (or the "plan of
    reorganization" within the meaning of Treas. Reg. Section1.368-1(c) with
    respect to the Merger) are funded directly or indirectly by a party other
    than the incurring party, such expenses will be within the guidelines
    established in Revenue Ruling 73-54, 1973-1 C.B. 187; any expenses paid on
    behalf of InfoSpinner stockholders will not exceed one percent (1%) of the
    total consideration that will be issued in the Merger to InfoSpinner
    stockholders in exchange for their shares of InfoSpinner capital stock;
 
        G. No InfoSpinner stockholder guaranteed any InfoSpinner indebtedness
    outstanding during the period immediately prior to the Merger, and at all
    relevant times, including as of the Effective Time, (i) no outstanding
    indebtedness of InfoSpinner, Centura or Sub has or will represent equity for
    tax purposes; (ii) no outstanding equity of InfoSpinner, Centura or Sub has
    or will represent indebtedness for tax purposes; and (iii) no outstanding
    security, instrument, agreement or arrangement that provides for, contains,
    or represents either a right to acquire InfoSpinner capital stock or to
    share in the appreciation thereof constitutes or will constitute "stock" for
    purposes of Section 368(c) of the Code; and
 
   
        H. The GDSVF&H Tax Opinion has been delivered and will not be withdrawn
    prior to the consummation of the Merger.
    
 
    Based on our examination of the foregoing items and subject to the
assumptions, exceptions, limitations and qualifications set forth herein, we are
of the opinion that, for federal income tax purposes, the Merger will be a
"reorganization" as defined in Section 368(a) of the Code.
 
    In addition to the assumptions set forth above, this opinion is subject to
the exceptions, limitations and qualifications set forth below.
 
    1.  This opinion represents and is based upon our best judgment regarding
the application of federal income tax laws arising under the Code, existing
judicial decisions, administrative regulations and published rulings and
procedures. Our opinion is not binding upon the Internal Revenue Service or the
courts, and there is no assurance that the Internal Revenue Service will not
successfully assert a contrary position. Furthermore, no assurance can be given
that future legislative, judicial or administrative changes, on either a
prospective or retroactive basis, would not adversely affect the accuracy of the
conclusions stated herein. Nevertheless, we undertake no responsibility to
advise you of any new developments in the application or interpretation of the
federal income tax laws.
 
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    2.  This opinion addresses only the classification of the Merger as a
reorganization under Section 368(a) of the Code, and does not address any other
federal, state, local or foreign tax consequences that may result from the
Merger or any other transaction (including any transaction undertaken in
connection with the Merger). In particular, but without limitation, we express
no opinion regarding, (i) whether and the extent to which any InfoSpinner
stockholder who has provided or will provide services to InfoSpinner, Centura or
Sub will have compensation income under any provision of the Code; (ii) the
effects of such compensation income, including but not limited to the effect
upon the basis and holding period of the Centura Common Stock received by any
such stockholder in the Merger; (iii) the potential application of the "golden
parachute" provisions (Sections 280G, 3121(v)(2) and 4999) of the Code, the
alternative minimum tax provisions (Sections 55, 56 and 57) of the Code or
Sections 305, 306, 357, 424, and 708, or the regulations promulgated thereunder;
(iv) the corporate level tax consequences of the Merger to Centura, Sub or
InfoSpinner, including without limitation the recognition of any gain and the
survival and/ or availability, after the Merger, of any of the federal income
tax attributes or elections of InfoSpinner, after application of any provision
of the Code, as well as the regulations promulgated thereunder and judicial
interpretations thereof; (v) the basis of any equity interest in InfoSpinner
acquired by Centura in the Merger; (vi) the tax consequences of any transaction
in which InfoSpinner capital stock or a right to acquire InfoSpinner capital
stock was received; (vii) the tax consequences to any InfoSpinner stockholder or
to InfoSpinner, Centura or Sub of a forfeiture to Centura of all or any part of
the Escrow Shares; and (viii) the tax consequences of the Merger (including the
opinion set forth above) as applied to stockholders of InfoSpinner and/or
holders of options or warrants for InfoSpinner capital stock or that may be
relevant to particular classes of InfoSpinner stockholders and/or holders of
options or warrants for InfoSpinner capital stock such as dealers in securities,
corporate stockholders subject to the alternative minimum tax, foreign persons,
and holders of shares acquired upon exercise of stock options or in other
compensatory transactions.
 
   
    3.  No opinion is expressed as to any transaction other than the Merger as
described in the Merger Agreements or to any transaction whatsoever, including
the Merger, if all the transactions described in the Merger Agreements are not
consummated in accordance with the terms of such Merger Agreements and without
waiver or breach of any material provision thereof or if all of the
representations, warranties, statements and assumptions upon which we relied are
not true and accurate at all relevant times. In the event any one of the
statements, representations, warranties or assumptions upon which we have relied
to issue this opinion is incorrect, our opinion might be adversely affected and
may not be relied upon. In addition, in the event that executed copies of the
letters and agreements referred to in 2, 3 or 4 of the third paragraph of this
letter are not furnished to us at or prior to the Effective Time, this opinion
shall be void and of no further effect, and may not be relied upon.
    
 
   
    4.  This opinion has been delivered to you for the purpose of satisfying the
condition set forth in Section 6.1(h) of the Agreement and is intended solely
for your benefit; it may not be relied upon for any other purpose or by any
other person or entity, and may not be made available to any other person or
entity without our prior written consent, except that we hereby consent to the
filing of this opinion as an exhibit to the Form S-4 Registration Statement to
be filed with the Securities and Exchange Commission with respect to the
securities described herein and to the references to this form in the section
entitled "Certain Federal Income Tax Consequences of the Merger" thereof. This
consent is not to be construed as an admission that we are a person whose
consent is required to be filed with the registration statement under the
provisions of the Securities Act of 1933.
    
 
                                          Very truly yours,
 
   
                                          /S/ VENTURE LAW GROUP
    
 
                                          VENTURE LAW GROUP,
                                          A PROFESSIONAL CORPORATION
 
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