Exhibit 4.3
                                                                                

                        EMPLOYEE STOCKHOLDERS' AGREEMENT
                           (Redemption and Buy-Sell)
                                      FOR

                                    DOS LTD.


     THIS AGREEMENT, made as of this ____ day of ______________, 1993, by and
among DOS, Ltd., a Bermuda corporation (hereinafter referred to as "DOSL"), and
__________________ (hereinafter referred to as the "Shareholder").

                              W I T N E S S E T H:

     WHEREAS, for good and valuable consideration, DOSL and the Shareholder have
agreed to impose certain restrictions on said capital stock: and

     WHEREAS, the Shareholder agrees that it is to his benefit and in the best
interests of DOSL to restrict the assignability of the capital stock of DOSL
issued pursuant to the DOS Ltd. 1993 Stock Option Plan, to provide for the
control and disposition of DOSL, to provide for the orderly transition of
ownership in the event of death, disability or retirement of a Shareholder, or
other termination of a Shareholder's capital stock under certain specified
conditions, and to provide the funds necessary to carry out such purchases.

     NOW, THEREFORE, in consideration of the mutual agreements contained herein
and for other valuable consideration, the sufficiency and receipt of which is
hereby acknowledged, it is mutually agreed by and among the parties to this
Agreement as follows:

     I.   DEFINITIONS
          -----------

          The following definitions shall control the meanings of the respective
          terms:

          A.   "Termination" or "Terminating" means to the extent applicable
               according to the provisions hereof, retirement, loss of
               employment from Corporation or its wholly owned subsidiaries,
               death, or Assignment or other transfer of an Ownership Interest
               (or any part thereof), and includes dissolution of marriage or
               permanent separation.  A call to military services shall be a
               "termination" only to the extent allowed under the Solders and
               Sailors Relief Act.

          B.   "Assignment or other transfer" includes, but is not limited to,
               sale, exchange, hypothecation, collateral assignment, subjecting
               the ownership interest to a security interest, attachment,
               judgment, creditor execution, bankruptcy, or other similar
               occurrence sanctioned by the law, without the advance consent in
               writing of the Committee.

          C.   "Committee" means the group of three or more individuals
               appointed by the Board of Directors of DOSL.  The Committee shall
               have sole

 
               authority to select the individuals who are to be granted Options
               from among those eligible hereunder and to establish the number
               of shares which may be issued under each Option.  The Committee
               has the authority to designate whether all or a portion of the
               Options granted under the Plan shall be Incentive Stock options
               or nonqualified stock options.  The Committee is authorized to
               interpret the Plan and may from time to time adopt such rules and
               regulations, consistent with the provisions of the Plan, as it
               may deem advisable to carry out the Plan.  All decisions made by
               the Committee in selecting the individuals to whom Options shall
               be granted, in establishing the number of shares which may be
               issued under each Option and in construing the provisions of the
               Plan shall be final.  If a Committee is not appointed by the
               Board, the Board shall act as the Committee for purposes of the
               Plan.

          D.   "Terminating Shareholder" or "Offering Shareholder" means the
               Shareholder who is terminating his interest in DOSL.  It
               includes, as required, the estate of a deceased Shareholder
               acting through its personal representative, which shall also be
               referred to as "Deceased Shareholder", or the Trustee (by trust,
               or in bankruptcy), receiver, or other legal representative of the
               Terminating Shareholder who has the power to act.

          E.   "Ownership Interest" means the equity interest that each
               Shareholder has in DOSL which is reflected by stock ownership,
               regardless of class or series.

          F.   "Debt" means the obligation of DOSL to repay a loan made to DOSL
               by a Shareholder.  Unless otherwise expressly stated herein, the
               debt shall be repaid according to its terms at the interest rate,
               interest dates, and maturity date fixed in the note, but if the
               note is payable on demand, is in default at the termination date,
               or past maturity, the debt shall be repaid upon the terms, at the
               interest rate, and upon the dates on which the payments in
               exchange for the Terminating Shareholder's Ownership Interest are
               made: being, for example, prorated over the installments due for
               the Terminating Shareholder's Ownership Interest.

          G.   "Receipt" or "Received" refers to the date received.  In the
               event of a dispute as to the date received, if mailed by ordinary
               mail, the date of receipt is three days after the postmark date;
               otherwise it is the date shown on the return receipt.

               Unless otherwise stated specifically herein, any time period
               shall commence, run, and expire at 12:00 midnight, central
               standard time, within the stated days or months, whether the
               offer acceptance, or other act is to or by the Terminating
               Shareholder, DOSL, or the Continuing Shareholders, acting jointly
               or separately, simultaneously or

                                       2

 
               consecutively, and regardless of which party or parties is
               entitled to the first offer.  All "days" shall refer to calendar
               days.

          H.   "Closing" or "Closing Date" shall mean the first business day
               after the tenth day after the acceptance of an offer hereunder.

II.  GENERAL TERMS
     -------------

          A.   Delegation to Other Contractual Agreements
               ------------------------------------------

               Unless expressly provided herein otherwise, nothing contained in
               this Agreement shall discharge, release, or otherwise change,
               amend, or alter any sums due, or rights under any employment
               contract or other employment arrangement between DOSL and any
               Shareholder.  Further, no other contractual relationship between
               DOSL and a Shareholder or among any or all of them shall be
               affected by this Agreement save one that attempts to define or
               speak to the terms of this Agreement, in which case the other
               contract shall be null and void unless it is in writing, it
               expressly indicates that it is amending this Agreement, and it is
               signed by DOSL.

          B.   Redemption Agreement
               --------------------

               This Agreement is intended to be a redemption agreement, and all
               offers required to be made hereunder shall first be made to DOSL.
               If DOSL is willing to accept the offer but does not have the
               financial means to accomplish the acceptance, then the remaining
               Shareholders shall have the right, but not the duty, to provide
               to DOSL sufficient funding, in the amounts and in the manner
               agreed upon between themselves, so that DOSL may accept the offer
               in the first instance.  If DOSL is for any reason unable or
               unwilling to accept the offer, the offer shall next be made to
               any other third party, subject to the restrictions, terms and
               conditions as provided herein.

          C.   Status of Assignees, Transferees, etc.
               --------------------------------------

               All (i) assignees, transferees, trustees, receivers, or others
               who obtain an interest in the shares, whether by attachment,
               execution, bankruptcy law, receivership law, or otherwise by
               operation of law, and (ii) assignees, transferees, secured
               parties, creditors, and other who obtain an interest in the
               shares, whether or not said Assignment or other transfer occurred
               with the consent of the Continuing Shareholders, take subject to
               the terms and conditions of this Agreement and subject to
               qualifications under any applicable provision of the Securities
               Exchange Commission and/or any state securities agency.  Any such
               act of Assignment or other transfer, whether by operation of law,
               voluntarily or involuntarily, or by act of a

                                       3

 
               Shareholder if not consented to, any act, demand, or attempt to
               realize upon the collateral security of the shares, shall result
               in the party succeeding to or attempting to succeed to the
               Ownership of such Shareholder, becoming a Terminating
               Shareholder, and the act, as described in this sentence, shall
               constitute a Termination Event, so that the terms and conditions
               of this Agreement shall apply.

          D.   Offers, Acceptances and Communications
               --------------------------------------

               All offers, acceptances, communications, and the like between
               DOSL and a Terminating Shareholder shall be in writing.  Such
               writing shall contain all pertinent particulars, including, as
               applicable, selling price, dates, terms and conditions.

          E.   Status of Spouse.
               ---------------- 

               It is recognized that inasmuch as some the Shareholders are
               married, and inasmuch as some of the Shareholders may become
               married, their respective spouses may have an interest in any or
               all shares of capital stock of DOSL held by the Shareholder to
               the extent such shares constitute or become community property,
               or are held in joint tenancy or as tenants by the entireties
               (included herein as "Community Property") by reason of their
               respective spouses' rights to acquire, manage, control, or
               dispose of Community Property.  Therefore, each of the
               Shareholders hereby agree and consent to the requirement that if
               they are currently married, or upon their marriage, they will
               cause their respective spouses to consent to the terms hereof, as
               such may affect the interest of their respective spouses and
               evidence such consent in writing by executing a copy of this
               Agreement.  In the event that circumstances cause the terms of
               this Agreement to be operative, whereby a Terminating Shareholder
               is required to offer his Ownership Interest to DOSL, the spouse
               of the Terminating Shareholder shall in like manner and upon the
               same terms and conditions as provided herein offer any Ownership
               Interest in said shares.

III. CERTAIN TERMINATING EVENTS
     --------------------------

          The following terms and conditions shall control upon the occurrence
          of any of the following Terminating events with respect to a
          Shareholder:

          A.   Retirement
               ----------

               If a Shareholder is at the date hereof an employee of DOSL or any
               of its wholly owned subsidiaries, or thereafter becomes an
               employee of DOSL and subsequently retires from such employment,
               he must offer (or be deemed to have offered automatically) to
               DOSL his Ownership Interest within thirty (30) days after his
               retirement; provided, however,

                                       4

 
               notwithstanding any other provisions hereof, the purchase of a
               Retired Shareholder's interest by DOSL shall be optional and
               evidence of DOSL's decision to accept or decline such purchase
               shall be communicated to the Retired Shareholder pursuant to part
               three (3.) hereof, and the following provisions shall apply:

               1.   The purchase price, the terms of purchase, the interest
                    rate, the security, and the like shall be as provided in
                    Section VII hereof.

               2.   Unless the Retired Shareholder shall consent otherwise,
                    DOSL, if it elects to purchase, shall purchase all 100% of
                    the Retired Shareholder's Ownership Interest.

               3.   Acceptance of the offer by DOSL shall be delivered to the
                    Retired Shareholder on or before the sixtieth (60th) day
                    next succeeding the date DOSL receives the Retired
                    Shareholder's offer.  If no written offer is given to DOSL
                    within the thirty day period, DOSL will be deemed to have
                    received notice on the 30th day following the retirement.

               4.   If DOSL does not accept the offer by the 60th day,
                    Shareholder may sell his shares to any party he/she desires
                    at any price.

          B.   Severance of Employment
               -----------------------

               If a Shareholder is at the date hereof an employee of DOSL or
               thereafter becomes an employee of DOSL and subsequently such
               employment is severed for reasons other than retirement, whether
               or not the severance is by mutual consent or otherwise, the
               Terminating Shareholder shall offer (or be deemed to have offered
               automatically) his Ownership Interest to DOSL.  The offer period
               shall be measured from the date of the last day of his
               employment, and the same terms and conditions as are provided in
               respect of the Retirement of a Shareholder in subparagraphs 1-4
               of Paragraph A to this Section III shall apply, with the term
               "Terminating Shareholder" being substituted for the term "Retired
               Shareholder."

          C.   Divorce or Permanent Separation
               -------------------------------

               In the event that a petition is filed in a court of competent
               jurisdiction seeking a divorce or permanent separation, by or
               against a Shareholder, such Terminating Shareholder shall offer
               (or be deemed to have offered automatically) his Ownership
               Interest to DOSL.  The offer period shall be measured from the
               date of the filing of such petition, or the date the Terminating
               Shareholder shall have received notice of same, whichever is
               later, and the same terms and conditions as are provided in
               respect of the Retirement of a Shareholder in subparagraphs 1-4
               of Paragraph A

                                       5

 
               of this Section III shall apply with the term "Terminating
               Shareholder" being substituted for the term "Retired
               Shareholder."

     IV.  ASSIGNMENT OR OTHER TRANSFER
          ----------------------------

          Prior to the occurrence of a Terminating Event, the Ownership Interest
          held by Shareholder is not transferable or assignable in any way other
          than by will or the laws of descent and distribution unless agreed to
          by DOSL in writing and signed by an officer of DOSL.  Any such
          transfer or assignment shall also be subject to the recipient of such
          shares qualifying with any applicable provision of the Securities
          Exchange Commission or any applicable state securities agency.

     V.   DEATH AS A TERMINATING EVENT
          ----------------------------

          If a Shareholder dies, the Deceased Shareholder, through this personal
          representative, shall offer (or be deemed to have offered
          automatically) to DOSL his Ownership Interest in DOSL, and the
          following provisions shall apply:

          A.   Offer
               -----

               The offer shall be made as soon as practical after the
               appointment of the decedent's personal representative, but in no
               event later than one hundred and twenty (120) days after the
               decedent's death.

          B.   Purchase Price
               --------------

               The purchase price, the terms of purchase, the interest, the
               security, and the like shall be as provided in Section VII
               hereof.

          C.   Purchase
               --------

               Unless the Deceased Shareholder, through his personal
               representative, shall consent otherwise, DOSL, if it elects to
               purchase, shall purchase all (1005) of the Deceased Shareholder's
               Ownership Interest.

          D.   Acceptance
               ----------

               Acceptance of the offer by DOSL shall be delivered to the
               personal representative of the Deceased Shareholder on or before
               the thirtieth (30th) day next succeeding the later of (a) the
               date DOSL received the Deceased Shareholder's offer, through his
               personal representative, or (b) one hundred and twenty (120) days
               after the death of the Shareholder.

     VI.  Restrictions
          ------------

                                       6

 
               The share certificates shall bear the following legend or a
               legend to the following effect:

               "The transfer of these shares is restricted.  These shares may be
               restricted under the terms of the Securities Act of 1933, the
               Securities and Exchange Act of 1934, or the Securities Act of
               Texas (collectively called the "Securities Acts").  The
               restriction may involve limitations required under an exemption
               from said Security Acts, such as an investment representation, a
               residence requirement, or a holding period requirement under the
               Intrastate Offering exemption."

               "Further, the transfer of these shares is restricted under the
               terms of a Stock Redemption and Buy-Sell Agreement (also referred
               to as the "Employee Stockholders' Agreement") between the holder
               of this certificate and DOSL or other shareholders, or both.
               Said shares may be not sold, transferred, assigned, given away,
               pledged, encumbered, or otherwise disposed of except in strict
               accordance with the terms of that agreement, and no transfer will
               be recognized by DOS Ltd., until, as the case may be, counsel to
               DOS Ltd. is satisfied there is no violation of the Security Acts,
               the other shareholders consent to the transfer, or both."

          B.   Additionally, the transfer of shares will be restricted as
               follows:

               After execution of the required Agreements, and upon issuance of
               the shares, Optionee and his spouse will be prohibited form
               selling, assigning or transferring in any way their interest in
               the shares for a period of six months without the express written
               approval from the Committee.  The Committee will have the sole
               authority to grant a waiver from the six month restriction and
               its decision will be final.  Request for waiver of the
               restriction must be made in writing and notice delivered to the
               Committee.

     VII. PURCHASE PRICE AND TERMS
          ------------------------

          A.   Redemption Valuation
               --------------------

               The redemption value of the shares will be set by the Committee
               on a semi-annual basis.  The Committee shall have the sole
               authority to establish the price at which any shares are
               repurchased or redeemed under the terms of this Agreement, and
               all decisions made by the Committee in setting the value of each
               share of Stock shall be final.

               If, after an option has been exercise, the shares are to be
               redeemed and the shares have been publicly traded for at least 30
               days, the redemption value of the shares will be the average
               between the high

                                       7

 
               and low (or if applicable, closing bid and asked price) price per
               share for the last 20 trading days prior to the terminating
               event.

          B.  Payment
              -------

               In the case of a Termination other than by reason of death, the
               purchase price shall be paid as follows:  fifteen percent (15%)
               of the purchase price paid at Closing, with the balance paid in
               five (5) equal and consecutive annual installments, to commence
               on the first business day of the next succeeding fiscal year of
               DOSL in after the Closing.  The unpaid principal shall bear six
               percent (6%) simple annual interest payable on each principal
               installment date.  In default of either a principal installment
               or the interest due in respect thereof, the remaining balance of
               the purchase price may become due and payable at  the option of
               the noteholder upon providing 30 days notice to DOSL and an
               opportunity to cure.  The entire principal balance or any part
               thereof may be prepaid without penalty.  All costs and expenses
               which arise in connection with collection of any amounts due
               shall be borne by the maker of the note, including a reasonable
               attorney's fee.  The note to be used shall be approved by DOSL's
               attorney.

          C.   Escrow
               ------

               The Ownership Interest being sold to DOSL and all indicia
               thereof, shall, at the election of the Terminating Shareholder,
               be retained in escrow by a disinterested third party selected by
               mutual agreement between the Terminating Shareholder and DOSL
               with appropriate escrow instructions to the effect that the
               Ownership Interest shall be delivered to DOSL when the purchase
               price, together with any accrued interest, has been paid in full,
               and, in the event of default thereof, the Ownership Interest
               amount equal to the percentage of the unpaid principal amount
               shall revert to the Terminating Shareholder.  However, so long as
               no default occurs, any voting rights or other interests accruing
               to DOSL by reason of its purchase of such stock shall be fully
               exercisable by it.

          D.   Secured Transaction
               -------------------

               The terms of Article 9 of the Uniform Commercial Code, dealing
               with default and the taking of collateral, then applying in the
               State of Texas shall govern the Terminating Shareholder's and
               DOSl's rights and remedies in the event of default.

          E.   Tax Status
               ----------

                                       8

 
               All proceeds payable to a Terminating Shareholder shall be
               regarded for income tax purposes as paid from the following
               sources, in the order of priority shown:

               1.   First, to the extent thereof, the Terminating Shareholder
                    shall receive the balance of his salary or other employee
                    compensation, if any, including expense reimbursement but
                    excluding a qualified employee plan distribution, due and
                    owing to him for the period involved.

               2.   Second, as to the balance, the Terminating Shareholder shall
                    receive payment for his shares.

     VIII.  RESIGNATIONS
            ------------

          Effective upon the occurrence of a Terminating event, the Terminating
          Shareholder and his spouse will automatically be deemed to have
          resigned as a director or officer of DOSL as the case may be, and such
          resignation shall be effective without further act of the Terminating
          Shareholder or his spouse.  Each Shareholder confers a power of
          attorney upon DOSL and agrees that upon the occurrence of the above
          events, DOSL shall thereafter have the power to do the things and
          perform the acts which may be necessary to reflect the fact that
          neither the Terminating Shareholder nor his spouse is an officer or
          director of DOSL.

          Nothing herein, however, shall act as a waiver of or release of any
          claim, demand, or assertion of the Terminating Shareholder against
          DOSL for salary, expense reimbursement, or similar employee benefits,
          to the extent he is entitled to the same.

     IX.  NON-INTERFERENCE
          ----------------

          A.   Covenants of Terminating Shareholder
               ------------------------------------

               Notwithstanding that the balance of the purchase price may be due
               and payable to the Terminating Shareholder and the Ownership
               Interest is held in escrow as collateral security, the continuing
               interest of the Terminating Shareholder shall be solely a secured
               interest protecting a debt due.  The Terminating Shareholder
               shall be solely a secured interest protecting a debt due.   The
               Terminating Shareholder shall not have any say or right in
               management, and he agrees to execute whatever documents,
               instruments, and papers shall reasonably be required by the
               attorney for DOSL to reflect the Terminating Shareholder has
               severed all relationship and connection with DOSL save as a
               creditor.  DOSL and the Terminating Shareholder shall each have
               the right to send notices of the severance of the relationship.

                                       9

 
          B.   Mutual Covenants
               ----------------

               DOSL and the Terminating Shareholder hereby mutually exchange
               covenants of non-interference and each agrees to refrain from any
               conduct, by word or act, that will reflect negatively on the
               character or conduct of the other.

          C.   Non-Competition
               ---------------

               The Terminating Shareholder, recognizing that a covenant not to
               compete is required to protect the business interests of DOSL
               agrees that unless DOSL consents in writing to the contrary, such
               Terminating Shareholder shall not engage in a competing business
               within fifty (50) miles of the office or location where he most
               recently employed by DOSL or its subsidiaries, for twelve months
               (365 successive calendar days) after the Closing of the purchase
               transaction.  A "competing business" shall mean and include a
               business similar or directly related to the active trade or
               business of DOSL or any subsidiary of DOSL.  It shall cover
               employment, management, and investment in any such competing
               business.

          D.   Reasonableness
               --------------

               DOSL and all the Shareholders expressly agree that because of the
               nature of DOSL, the above restrictions in Paragraph C as to area
               and time are reasonable.

          E.   Preservation of Name
               --------------------

               DOSL now has and shall continue to have, the sole and exclusive
               right to use the name "DOS Ltd." as its corporate name and title.
               This right shall not be affected by the termination of
               association with DOSL of any Shareholder, either as a
               shareholder, officer, director, or employee, nor by any other
               cause.  In the event that any Shareholder ceases to be associated
               with or employed by DOSL or any of its subsidiaries for any
               reason, they agree herein and hereby to not thereafter use or
               permit the use of the name "DOS Ltd.", or any of its
               subsidiaries, in the name or trademark of any Corporation,
               partnership, or other business with which they are associated in
               any capacity, directly or indirectly, and which is engaged in a
               business similar in any respect to that conducted by DOSL or any
               of its subsidiaries, unless such name or trademark includes other
               words denoting that such business is a separate organization,
               business, or entity entirely distinct from and not to be confused
               with DOSL, and unless such name or trademark does not contain any
               words stating or suggesting prior or current affiliate or
               connection with, or comparison in age, business, or otherwise
               with DOSL.

                                       10

 
     F.  Confidentiality
         ---------------

          It is also recognized and acknowledged by the Shareholders that
          confidential information pertaining to DOSL's customers and
          manufacturing processes which  may be available to them is valuable,
          special and unique except as such may be in the public domain.
          Accordingly, the Shareholders hereby agree that they will not at any
          time disclose any of such information to any person, firm,
          Corporation, association or other entity for any reason or purpose
          whatsoever or make use in any other way to his advantage of such
          information.

     X.   MISCELLANEOUS MATTERS
          ---------------------

          A.   Mutual Release
               --------------

               The Terminating Shareholder, for his part, and DOSL and the
               Continuing Shareholders, for their part, do each release and
               acquit the other of any and all claims that each may have against
               the other, save and except the obligations set forth in the
               Agreement.  It is the intention of the parties hereto that once
               this Agreement becomes effective, each of the parties will look
               only to the rights that he or they have under this Agreement.

          B.   Insurance Policies
               ------------------

               If DOSL is the owner and beneficiary of insurance policies on the
               life of the Shareholder, DOSL may continue to maintain such
               insurance in force and effect during the lifetime of each insured
               Shareholder.  DOSL shall have the right to obtain additional
               insurance on the lives of the Shareholders whenever, in the
               opinion of DOSL, additional insurance may be required for the
               benefit of DOSL or to enable it to carry out its obligations
               under this Agreement.

          C.   Rights to Purchase Policies
               ---------------------------

               A Terminating Shareholder shall have the right to purchase the
               policy or policies carried by DOSL on his own life by paying to
               DOSL an amount equal to the then net cash surrender value of such
               policy or policies plus the unearned portion of any premiums that
               may have been paid thereon.  Such right of purchase shall be
               exercised by notice given to DOSL, in writing, within thirty (30)
               days after the Closing Date of the purchase of such Terminating
               Shareholder's Ownership Interest and the purchase price of the
               issuance shall be paid in full, in cash, within such period of
               time.  On receipt of the entire purchase price, DOSL will deliver
               the policies of insurance and will execute all necessary
               instruments of transfer.

          D.   Entire Agreement
               ----------------

                                       11

 
               This instrument contains the entire agreement of the parties
               hereto and supersedes all prior agreements made between the
               parties and DOSL affecting the capital stock of DOSL and all such
               prior agreements are hereby terminated.  No modification,
               amendment, change, or discharge of any term or provision of the
               Agreement shall be valid or binding unless the same is in writing
               and signed by all the parties hereto.  No waiver of any of the
               terms of the Agreement shall be valid unless signed by the party
               against whom such waiver is asserted.

          E.   Termination
               -----------

               This Agreement shall terminate on the occurrence of any of the
               following events:

               1.   Bankruptcy, receivership, or dissolution of DOSL.

               2.   The voluntary agreement of all of the Shareholders.

          F.   Binding Effect
               --------------

               This Agreement shall be binding upon and inure to the benefit of
               the parties and their heirs, legal representative, successors,
               and assigns, and the parties agree for themselves and their
               heirs, legal representatives, successors, and assigns to execute
               any instruments in writing which may be necessary or proper in
               carrying out the purposes of the Agreements.

          G.   Applicable Law
               --------------

               The parties mutually covenant and agree that this Agreement shall
               be subject to and governed by the laws of the State of Texas,
               irrespective of the fact that one or more of the parties now is
               or may become a resident of a different state.

          H.   Invalidity
               ----------

               The invalidity or uneforceability of any particular provision of
               this Agreement shall not affect the other provisions hereof, and
               the Agreement shall be construed in all respects as if such
               invalid or unenforceable provisions were omitted.

          I.   Gender
               ------

               Words of any gender used in this Agreement shall be held and
               construed to include any other gender, and words in the singular
               shall be held and construed to include the plural, unless the
               context otherwise requires.

                                       12

 
          J.  Headings
              --------

               The captions or headings contained in this Agreement are inserted
               and included solely for convenience and shall never be considered
               or given any effect in construing the provisions hereof if any
               question of intent should arise.

          K.   Repurchase After Divorce
               ------------------------

               In the event a Shareholder's Ownership Interest is purchased by
               DOSL by reason of the Terminating Shareholder's divorce or
               permanent separation pursuant to the terms of the Agreement, such
               Terminating Shareholder shall have the exclusive right to
               repurchase his or her entire Ownership Interest, including that
               of his spouse or any donees, following the entry of a final
               judgment and decree of divorce and the lapse of time allowed for
               any appeal thereof, provided no other terminating event occurs or
               has occurred.  Such purchase shall be effected by said
               Terminating Shareholder giving written notice to DOSL of his
               election to purchase all or any part of his Ownership Interest as
               herein provided and written notice thereof is given as provided
               above and actually received by DOSL within one (1) year from the
               date of Termination (which for purposes of this paragraph shall
               mean the date of Termination (which for purposes of this
               paragraph shall mean the date of the filing of any legal action
               regarding the Terminating Shareholder's divorce or permanent
               separation), the purchase price shall be the greater of the price
               originally paid by DOSL to the Terminating Shareholders, plus
               interest at six (6%) per annum or the current value as
               established by the committee.  The current value shall be
               determined as provided in Section VII, Paragraph A hereto, as of
               the date of the written notice of election.

          L.  Exhibits
              --------

               All exhibits, attachments, annexed instruments and addenda
               referred to herein shall be considered a part hereof for all
               purposes with the same force and effect as if copied at full
               length herein.

          M.   Venue and Applicable Law
               ------------------------

               This Agreement is made in the State of Texas and shall for all
               purposes be construed in accordance with the laws of the State of
               Texas.  Any cause of action based upon or relating to this
               Agreement in any way must be brought in Montgomery County, Texas
               within one (1) year of the accrual of the cause of action.  The
               prevailing party in any suit will be entitled to an award of its
               attorney's fees.

          N.   Attorney's Fees
               ---------------

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               Any party to this Agreement who is the prevailing party in any
               legal proceeding brought under or with relation to this Agreement
               or transaction shall be entitled to recover court costs and
               reasonable attorney's fees from the nonprevailing party.

          O.   Certain Shares
               --------------

               This Agreement applies only to those shares which have been
               purchased pursuant to the DOS Ltd. 1993 Stock Option Plan.

          IN WITNESS WHEREOF, the parties hereto warrant each to the other that
they have read this Agreement in its entirety, understand all its terms, and
execute this Agreement and its duplicate originals as of the date first above
written with full knowledge of its significance.


SHAREHOLDERS:                           RESPECTIVE SPOUSES:


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_________________________________       _________________________________


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ATTEST:


                                        By:
_________________________________       _________________________________
Secretary                                 President

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