EXHIBIT 10.1 
  
                           SHAREHOLDER AGREEMENT 
  
           SHAREHOLDER AGREEMENT (this "Agreement"), dated as of October
 [__], 1998, by and between Zitel Corporation, a California corporation
 ("Parent") and [___________] ("Shareholder").

                                 WITNESSETH: 
  
  
      WHEREAS, concurrently with the execution of this Agreement, Parent,
 Millennium Holding Corp. ("Holdco"), Millennium Acquisition I Corp., a
 Delaware corporation and a wholly-owned subsidiary of Holdco ("Millennium
 Acquisition"), Zenith Acquisition Corp., a Delaware corporation and a
 wholly-owned subsidiary of Holdco, and MatriDigm Corporation, a California
 corporation (the "Company") have entered into an Agreement and Plan of
 Reorganization and Merger, dated of even date herewith (the "Merger
 Agreement"), pursuant to which the parties thereto have agreed, among other
 things, to merge Millennium Acquisition with and into the Company upon the
 terms and subject to the conditions set forth therein (the "Millennium
 Merger"); and 
  
      WHEREAS, as of the date hereof, Shareholder is the record and
 Beneficial Owner (as defined hereinafter) of (i) [_________] shares of the
 Common Stock, no par value, of the Company (the "Common Stock"), and (ii)
 [_________] shares of the Preferred Stock, no par value, of the Company
 (the "Preferred Stock"); and 
  
      WHEREAS, as inducement and a condition to entering into the Merger
 Agreement, Parent has required Shareholder to agree, and Shareholder has
 agreed, to enter into this Agreement; and  
  
      WHEREAS, upon the terms and subject to the conditions set forth
 herein, Shareholder desires to (i) vote all such Shareholder's shares of
 Common Stock and Preferred Stock in favor of the Millennium Merger and the
 approval and adoption of the Merger Agreement and to execute a written
 consent in furtherance thereof, and (ii) as promptly as practicable
 hereafter, convert any shares of Preferred Stock held by such Shareholder
 into shares of Common Stock. 
  
      NOW, THEREFORE, in consideration of the foregoing and the mutual
 premises, representations, warranties, covenants and agreements contained
 herein, the parties hereto, intending to be legally bound hereby, agree as
 follows: 
  
           Section 1.  CERTAIN DEFINITIONS.  In addition to the terms
 defined elsewhere herein, capitalized terms used and not defined herein
 have the respective meanings ascribed to them in the Merger Agreement.  For
 purposes of this Agreement: 
  
                (a)  "Beneficially Own" or "Beneficial Ownership" with
 respect to any securities means having or sharing, directly or indirectly,
 through any contract, arrangement, understanding, relationship or
 otherwise, voting power, including the power to vote, or to direct the
 voting of, such securities, and/or investment power, including the power to
 dispose, or to direct the disposition, of such securities.  Without
 duplicative counting of the same securities by the same holder, securities
 Beneficially Owned by a person include securities Beneficially Owned by all
 other persons with whom such person acts in a partnership, limited
 partnership, syndicate or other group for the purpose of acquiring,
 holding, or disposing of securities of the same issuer. 
  
                (b)  "Existing Shares" means shares of Common Stock and
 Preferred Stock Beneficially Owned by Shareholder as of the date hereof. 
  
                (c)  "Securities" means the Existing Shares together with
 any shares of Common Stock, Preferred Stock or other securities of the
 Company acquired by Shareholder in any capacity after the date hereof and
 prior to the termination of this Agreement, whether upon the exercise of
 options, warrants or rights, the conversion or exchange of convertible or
 exchangeable securities, or by means of purchase, dividend, distribution,
 split-up, recapitalization, combination, exchange of shares or the like,
 gift, bequest, inheritance or as a successor in interest in any capacity or
 otherwise. 
  
           Section 2.  REPRESENTATIONS AND WARRANTIES OF SHAREHOLDER. 
 Shareholder represents and warrants to Parent as follows: 
  
                (a)  Ownership of Shares.  Except as set forth in Schedule
 2(a), Shareholder is the sole record and Beneficial Owner of the number of
 shares of Common Stock and Preferred Stock set forth opposite such
 Shareholder's name on Schedule A hereto.  Shareholder has sole voting power
 and sole power to issue instructions with respect to the matters set forth
 in Sections 5, 7 and 8 hereof, sole power of disposition, sole power of
 conversion, sole power to demand appraisal rights and sole power to agree
 to all of the matters set forth in this Agreement, in each case with
 respect to all of the Existing Shares with no limitations, qualifications
 or restrictions on such rights, subject to the terms of this Agreement. 
 Shareholder does not own any securities of the Company on the date hereof
 other than the shares of Common Stock and Preferred Stock set forth on
 Schedule A and the options to purchase share of Common Stock, if any,
 specified in Schedule 2(a). 
  
                (b)  Power; Binding Agreement.  Shareholder has the legal
 capacity, power and authority to enter into and perform all of
 Shareholder's obligations under this Agreement.  This Agreement has been
 duly and validly executed and delivered by Shareholder and constitutes a
 valid and binding agreement of Shareholder, enforceable against Shareholder
 in accordance with its terms except that (i) such enforcement may be
 subject to applicable bankruptcy, insolvency or other similar laws, now or
 hereafter in effect, affecting creditors' rights generally, and (ii) the
 remedy of specific performance and injunctive and other forms of equitable
 relief may be subject to equitable defenses and to the discretion of the
 court before which any proceeding therefor may be brought. 
  
                (c)  No Conflicts.  Except as disclosed in the Merger
 Agreement, no filing with, and no permit, authorization, consent or
 approval of, any state or federal public body or authority ("Governmental
 Entity") is necessary for the execution of this Agreement by Shareholder
 and the consummation by Shareholder of the transactions contemplated
 hereby, none of the execution and delivery of this Agreement by
 Shareholder, the consummation by Shareholder of the transactions
 contemplated hereby or compliance by Shareholder with any of the provisions
 hereof shall (i) conflict with or result in any breach of any
 organizational documents applicable to Shareholder, (ii) result in a
 violation or breach of, or constitute (with or without notice or lapse of
 time or both) a default (or give rise to any third party right of
 termination, cancellation, material modification or acceleration) under any
 of the terms, conditions or provisions of any note, loan agreement, bond,
 mortgage, indenture, license, contract, commitment, arrangement,
 understanding, agreement or other instrument or obligation of any kind to
 which Shareholder is a party or by which Shareholder or any of its
 properties or assets may be bound, or (iii) violate any order, writ,
 injunction, decree, judgment, order, statute, rule or regulation applicable
 to Shareholder or any of Shareholder's properties or assets. 
  
                (d)  No Encumbrance.  Except as permitted by this Agreement,
 the Existing Shares are now and, at all times during the term hereof, and
 the Securities will be, held by Shareholder or by a nominee or custodian
 for the benefit of Shareholder, free and clear of all mortgages, claims,
 charges, liens, security interests, pledges or options, proxies, voting
 trusts or agreements, understandings or arrangements or any other rights
 whatsoever (collectively, "Encumbrances"), except for any such Encumbrances
 arising hereunder. 
  
                (e)  No Finder's Fees.  No broker, investment banker,
 financial advisor or other person is entitled to any broker's, finder's,
 financial adviser's or other similar fee or commission in connection with
 the transactions contemplated hereby based upon arrangements made by or on
 behalf of Shareholder. 
  
                (f)  Reliance by Parent.  Shareholder understands and
 acknowledges that Parent is entering into the Merger Agreement in reliance
 upon Shareholder's execution and delivery of this Agreement. 
  
           Section 3.  REPRESENTATIONS AND WARRANTIES OF PARENT.  Parent
 hereby represents and warrants to Shareholder as follows: 
  
                (a)  Power; Binding Agreement. Parent has the corporate
 power and authority to enter into and perform all of its obligations under
 this Agreement.  This Agreement has been duly and validly executed and
 delivered by Parent and constitutes a valid and binding agreement of
 Parent, enforceable against Parent in accordance with its terms, except
 that (i) such enforcement may be subject to applicable bankruptcy,
 insolvency or other similar laws, now or hereafter in effect, affecting
 creditors' rights generally, and (ii) the remedy of specific performance
 and injunctive and other forms of equitable relief may be subject to
 equitable defenses and to the discretion of the court before which any
 proceeding therefor may be brought. 
  
                (b)  No Conflicts.  Except as disclosed in the Merger
 Agreement, no filing with, and no permit, authorization, consent or
 approval of, any Governmental Entity is necessary for the execution of this
 Agreement by Parent and the consummation by Parent of the transactions
 contemplated hereby, and none of the execution and delivery of this
 Agreement by each of Parent, the consummation by each of Parent of the
 transactions contemplated hereby or compliance by each of Parent with any
 of the provisions hereof shall (i) conflict with or result in any breach of
 any organizational documents applicable to Parent, (ii) result in a
 violation or breach of, or constitute (with or without notice or lapse of
 time or both) a default (or give rise to any third party right of
 termination, cancellation, material modification or acceleration) under any
 of the terms, conditions or provisions of any note, loan agreement, bond,
 mortgage, indenture, license, contract, commitment, arrangement,
 understanding, agreement or other instrument or obligation of any kind to
 which Parent is a party or by which Parent or any of its properties or
 assets may be bound, or (iii) violate any order, writ, injunction, decree,
 judgment, order, statute, rule or regulation applicable to Parent or any of
 its properties or assets. 
  
           Section 4.  DISCLOSURE.  Shareholder hereby agrees to permit
 Parent to publish and disclose in the Proxy Statement/Prospectus and any
 press release or other disclosure document which Parent, in its sole
 discretion, determines to be necessary or desirable in connection with the
 Millennium Merger and any transactions related thereto, Shareholder's
 identity and ownership of Common Stock and Preferred Stock, and the nature
 of Shareholder's commitments, arrangements and understandings under this
 Agreement. 
  
           Section 5.  CERTAIN PROHIBITED TRANSFERS.  Prior to the
 termination of this Agreement, Shareholder agrees not to, directly or
 indirectly: 
  
                (a)  except pursuant to the terms of the Merger Agreement or
 for distributions to the partners or members, as applicable, of
 Shareholder, offer for sale, sell, transfer, tender, pledge, encumber,
 assign or otherwise dispose of, or enter into any contract, option or other
 arrangement or understanding with respect to or consent to the offer for
 sale, sale, transfer, tender, pledge, encumbrance, assignment or other
 disposition of any or all of the Securities or any interest therein
 [including, without limitation, any sale, transfer or other disposition
 pursuant to the Founders Agreement (as defined in Section 8 hereof)];(1)

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(1)    Include in the Shareholder Agreement of each of the
       Founders only.
  
                (b)  grant any proxy, power of attorney, deposit any of the
 Securities into a voting trust or enter into a voting agreement or
 arrangement with respect to the Securities except as provided in this
 Agreement; or 
  
                (c)  take any other action that would make any
 representation or warranty of Shareholder contained herein untrue or
 incorrect or have the effect of preventing or disabling Shareholder from
 performing its obligations under this Agreement. 
  
           Section 6.  CONVERSION OF PREFERRED SHARES.  As promptly as
 practicable on or following the date hereof, Shareholder shall deliver or
 cause to be delivered to the Company all shares of Preferred Stock
 Beneficially Owned by such Shareholder, together with written instructions
 directing the Company to cause such shares to be converted into shares of
 Common Stock in accordance with the applicable provisions of the Company's
 Articles of Incorporation and in full satisfaction of all rights pertaining
 to such shares of Preferred Stock, such conversion to be effective no later
 than the business day immediately preceding the Effective Time of the
 Millennium Merger. 
  
           Section 7.  VOTING OF SECURITIES.  Shareholder hereby agrees
 that, during the period commencing on the date hereof and continuing until
 the first to occur of (a) the Effective Time, or (b) termination of this
 Agreement in accordance with its terms, in connection with the Consent
 Solicitation, Shareholder will vote or consent (or cause to be voted or
 consented) the Securities: 
  
                               (A)  in favor of the adoption of the Merger
           Agreement and the approval of the Millennium Merger and the other
           transactions contemplated by the Merger Agreement and this
           Agreement and any actions required in furtherance thereof and
           hereof;  
  
                               (B)  against any action or agreement that
           would result in a breach in any respect of any covenant,
           representation or warranty or any other obligation or agreement
           of the Company under the Merger Agreement or this Agreement; and  
  
                               (C)  except as otherwise agreed to in writing
           in advance by Parent in its sole discretion, against the
           following actions (other than the Millennium Merger and the
           transactions contemplated by this Agreement and the Merger
           Agreement): (1) any change in a majority of the persons who
           constitute the board of directors of the Company; (2) any
           material change in the present capitalization of the Company,
           including without limitation any proposal to sell a substantial
           equity interest in the Company; (3) any amendment of the
           Company's Articles of Incorporation or By-laws; (4) any other
           change in the Company's corporate structure or business; or (5)
           any other action which, in the case of each of the matters
           referred to in clauses (1), (2), (3) or (4), is intended, or
           could reasonably be expected, to impede, interfere with, delay,
           postpone or materially adversely affect the Millennium Merger and
           the transactions contemplated by this Agreement and the Merger
           Agreement.  Shareholder may not enter into any agreement or
           understanding with any person the effect of which would be
           inconsistent with or violative of any provision contained in this
           Section 7. 
  
           Section 8.  CONSENT SOLICITATION; FILING WITH SECRETARY. 
 Promptly following receipt thereof, Shareholder shall promptly execute and
 file such Shareholder's written consent to the Millennium Merger with the
 Secretary of the Company in accordance with the terms of the Consent
 Solicitation. 
  
           Section 9.  AFFILIATES AGREEMENT.  Promptly following the
 execution of this Agreement and no later than 10 days from the date hereof,
 Shareholder agrees to execute and deliver to Parent an Affiliates
 Agreement, substantially in the form attached as Exhibit E to the Merger
 Agreement. 
  
           [Section [ ]  WARRANT TO PURCHASE SERIES C COMPANY PREFERRED
 STOCK.  Shareholder agrees to execute all documents and to take all actions
 necessary to convert the Warrant to Purchase Series C Preferred Stock,
 dated as of May 17, 1996, held by Shareholder into that number of shares of
 Company Common Stock equal to the net number of shares of Company Common
 Stock into which such warrant would have been convertible pursuant to a
 cashless exercise procedure immediately prior to the Effective Time of the
 [Millennium Merger]  (2)
  
           [Section [ ]  WARRANT TO PURCHASE COMPANY COMMON STOCK. 
 Shareholder agrees to execute all documents and to take all actions
 necessary to convert the warrants granted in accordance with the Agreement
 to Guarantee, dated April 6, 1998, by and among the Company, Parent,
 Shareholder, BRC Holdings, Inc. and JBJ Partners, Inc., held by Shareholder
 into that number of shares of Company Common Stock equal to the net number
 of shares of Company Common Stock into which such warrant would have been
 convertible pursuant to a cashless exercise procedure immediately prior to
 the Effective Time of the Millennium Merger]  (3)

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(2)   Include in JBJ Shareholder Agreement only.

(3)   Include in BRC Shareholder Agreement and JBJ Partners
      Shareholder Agreement.
  
           Section 10.  PROXY.   
  
                (a)  Shareholder hereby irrevocably grants to, and appoints,
 Parent and Jack H. King and Henry C. Harris or any of them in their
 respective capacities as officers of Parent and any individual who shall
 hereafter succeed to any such office of Parent and each of them
 individually, such Shareholder's proxy and attorney-in-fact (with full
 power of substitution), for and in the name, place and stead of
 Shareholder, to grant a consent or approval in respect of the Securities in
 connection with the Consent Solicitation.   
  
                (b)  Shareholder understands and acknowledges that Parent is
 entering into the Merger Agreement in reliance upon such Shareholder's
 execution and delivery of this Agreement.  Shareholder hereby affirms that
 the irrevocable proxy set forth in this Section 10 is given in connection
 with the execution of the Merger Agreement, and that such irrevocable proxy
 is given to secure the performance of the duties of Shareholder under this
 Agreement.  Shareholder hereby further affirms that the irrevocable proxy
 is coupled with an interest and may under no circumstances be revoked. 
 Shareholder hereby ratifies and confirms all that such irrevocable proxy
 may lawfully do or cause to be done by virtue hereof.  Such irrevocable
 proxy is executed and intended to be irrevocable in accordance with the
 provisions of Section 705 of the General Corporation Law of the State of
 California. 
  
           Section 11.  STOP TRANSFER; LEGEND.   
  
                (a)  Shareholder agrees with, and covenants to, Parent that
 Shareholder will not request that the Company register the transfer of any
 certificate or uncertificated interest representing any of the Securities,
 unless such transfer is made in compliance with this Agreement. 
  
                (b)  In the event of a stock dividend or distribution, or
 any change in the Common Stock or Preferred Stock by reason of any stock
 dividend, split-up, recapitalization, combination, exchange of share or the
 like other than pursuant to the Millennium Merger, the term "Existing
 Shares" will be deemed to refer to and include the shares of Common Stock
 and Preferred Stock as well as all such stock dividends and distributions
 and any shares into which or for which any or all of the Securities may be
 changed or exchanged and appropriate adjustments shall be made to the terms
 and provisions of this Agreement. 
  
                (c)  Shareholder will promptly after the date hereof
 surrender to the Company all certificates representing the Securities, and
 the Company will place the following legend on such certificates in
 addition to any other legend required to be placed thereon: 
  
 "THE SECURITIES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO RESTRICTIONS
 ON TRANSFER SET FORTH IN THE SHAREHOLDER AGREEMENT, DATED AS OF OCTOBER
 [__], 1998, BY AND AMONG ZITEL CORPORATION AND [____________]." 
  
           Section 12.  BEST REASONABLE EFFORTS.  Subject to the terms and
 conditions of this Agreement, each of the parties hereto agrees to use its
 best reasonable efforts to take, or cause to be taken, all actions, and to
 do, or cause to be done, all things necessary, proper or advisable under
 applicable laws and regulations to consummate and make effective the
 transactions contemplated by this Agreement and the Merger Agreement.  Each
 party shall promptly consult with the other and provide any necessary
 information and material with respect to all filings made by such party
 with any Governmental Entity in connection with this Agreement and the
 Merger Agreement and the transactions contemplated hereby and thereby. 
  
           Section 13.  TERMINATION.  This Agreement shall terminate on the
 earliest of (a) termination of the Merger Agreement pursuant to its terms,
 (b) the agreement of the parties hereto to terminate this Agreement, or (c)
 the consummation of the Millennium Merger. 
  
           Section 14.  MISCELLANEOUS.   
  
                (a)  Entire Agreement.  This Agreement (including the
 documents and instruments referred to herein) constitutes the entire
 agreement and supersedes all other prior agreements and understandings,
 both written and oral, among the parties, or any of them, with respect to
 the subject matter hereof. 
  
                (b)  Successors and Assigns.  This Agreement shall not be
 assigned by operation of law or otherwise without the prior written consent
 of the other parties hereto.  This Agreement and the obligations set forth
 herein shall be binding upon each party's respective heirs, beneficiaries,
 executors, representatives and permitted assigns. 
  
                (c)  Amendment and Modification.  This Agreement may not be
 amended, altered, supplemented or otherwise modified or terminated except
 upon the execution and delivery of a written agreement executed by the
 parties hereto. 
  
                (d)  Notices.  All notices and other communications
 hereunder shall be in writing and shall be deemed given upon (i)
 transmitter's confirmation of a receipt of a facsimile transmission, (ii)
 confirmed delivery by a standard overnight carrier or when delivered by
 hand or (iii) the expiration of five business days after the day when
 mailed by certified or registered mail, postage prepaid, addressed at the
 following addresses (or at such other address for a party as shall be
 specified by like notice): 
  
      If to Parent, to: 
  
                Zitel Corporation 
                47211 Bayside Parkway 
                Fremont, California 94538 
                Attention:  Jack H. King 
                Facsimile:  (510) 440-8526 
  
           with a copy to: 
  
                Skadden, Arps, Slate, Meagher & Flom LLP 
                525 University Avenue, Suite 220 
                Palo Alto, California 94301 
                Attention: Kenton J. King, Esq. 
                Facsimile: 650-470-4570 
  
      If to Shareholder, to: 
  
                ________________________ 
                ________________________ 
                ________________________ 
                ________________________ 
  
           with a copy to: 
  
                ________________________ 
                ________________________ 
                ________________________ 
                ________________________ 
  
                (e)  Severability.  Any term or provision of this Agreement
 which is held to be invalid, illegal or unenforceable in any respect in any
 jurisdiction shall, as to that jurisdiction, be ineffective to the extent
 of such invalidity or unenforceability without rendering invalid or
 unenforceable the remaining terms and provisions of this Agreement or
 affecting the validity or enforceability of any of the terms or provisions
 of this Agreement in any other jurisdiction.  If any provision of this
 Agreement is so broad as to be unenforceable, the provision shall be
 interpreted to be only so broad as is enforceable. 
  
                (f)  Specific Performance.  Each of the parties hereto
 recognizes and acknowledges a breach by it of any covenants or agreements
 contained in this Agreement will cause the other party to sustain damages
 for which it would not have an adequate remedy at law for money, damages,
 and therefore in the event of any such breach the aggrieved party shall be
 entitled to the remedy of specified performance of such covenants and
 agreements and injunctive and other equitable relief in addition to any
 other remedy to which it may be entitled, at law or in equity.   
  
                (g)  No Waiver.  The failure of any party hereto to exercise
 any right, power or remedy provided under this Agreement or otherwise
 available in respect hereof at law or in equity, or to insist upon
 compliance by any other party hereto with its obligations hereunder, and
 any custom or practice of the parties at variance with the terms hereof,
 will not constitute a waiver by such party of its right to exercise any
 such or other right, power or remedy or to demand such compliance. 
  
                (h)  No Third Party Beneficiaries.  This Agreement is not
 intended to confer upon any person other than the parties hereto any rights
 or remedies hereunder. 
  
                (i)  Governing Law.  This Agreement shall be governed and
 construed in accordance with the laws of the State of California, without
 giving effect to the principles of conflict of law thereof. 
  
                (j)  Descriptive Heading.  The descriptive headings used
 herein are for reference purposes only and will not affect in any way the
 meaning or interpretation of this Agreement. 
  
                (k)  Expenses.  All costs and expenses incurred in
 connection with this Agreement and the transactions contemplated hereby
 shall be paid by the party incurring such expenses.   
  
                (l)  Further Assurances.  From time to time, at any other
 party's request and without further consideration, each party hereto shall
 execute and deliver such additional documents and take all such further
 lawful action as may be necessary or desirable to consummate and make
 effective, in the most expeditious manner practicable, the transactions
 contemplated by this Agreement. 
  
                (m)  Counterparts.  This Agreement may be executed in two or
 more counterparts, each of which shall be deemed to be an original, but all
 of which together shall constitute one and the same instrument.

           IN WITNESS WHEREOF, Parent and Shareholder have caused this
 Agreement to be duly executed as of the day and year first written above. 
  
  
                                 ZITEL CORPORATION 
  
  
  
                                 By: ____________________________ 
                                    Name: 
                                    Title: 
  
  
  
                                 By: ____________________________ 
                                     [Shareholder] (4)

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(4)     In the event this Agreement covers shares held
        jointly or held individually by related parties who will
        sign this together, each joint or related party shall
        sign.