THE SECURITIES  REPRESENTED BY THIS CERTIFICATE (THE "SECURITIES") HAVE NOT BEEN
REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES  ACT"),
OR STATE SECURITIES LAWS AND MAY NOT BE SOLD,  TRANSFERRED,  ASSIGNED,  PLEDGED,
HYPOTHECATED OR OTHERWISE DISPOSED OF UNLESS REGISTERED UNDER THE SECURITIES ACT
AND UNDER APPLICABLE STATE SECURITIES LAWS OR XYBERNAUT CORPORATION,  A DELAWARE
CORPORATION (THE  "COMPANY"),  SHALL HAVE RECEIVED AN OPINION IN FORM, SCOPE AND
SUBSTANCE  REASONABLY  ACCEPTABLE TO THE COMPANY, OF COUNSEL,  WHO IS REASONABLY
ACCEPTABLE TO THE COMPANY,  THE PROPOSED  SALE,  TRANSFER,  ASSIGNMENT,  PLEDGE,
HYPOTHECATION  OR OTHER  DISPOSITION  IS  EXEMPT  FROM  REGISTRATION  UNDER  THE
SECURITIES  ACT AND  UNDER  THE  PROVISIONS  OF  APPLICABLE  FEDERAL  AND  STATE
SECURITIES LAWS.


                          COMMON STOCK PURCHASE WARRANT


                              XYBERNAUT CORPORATION


                             Expires April 18, 2006


No.:  W-00001                                         Number of Shares:  200,000
Date of Issuance:  April 18, 2001

1.   Issuance. In consideration of good and valuable consideration,  the receipt
     of which is  hereby  acknowledged  by  Xybernaut  Corporation,  a  Delaware
     corporation  (the  "Company"),  Texas  Instruments  Incorporated,   or  its
     registered assigns (the "Holder"),  is hereby granted the right to purchase
     at any time  until 5:00 P.M.,  New York City time,  on April 18,  2006 (the
     "Expiration   Date"),   Two  Hundred  Thousand  (200,000)  fully  paid  and
     nonassessable  shares (the "Warrant Shares") of the Company's Common Stock,
     par value $.01 per share (the  "Common  Stock"),  at an exercise  price per
     share equal to $5.00 (the "Exercise Price").

     The Exercise  Price and the number of Warrant Shares for which this Warrant
     is  exercisable  shall be subject to  adjustment as provided  herein.  This
     Warrant is being  issued in  connection  with Speech  Recognition  Software
     License Agreement dated as of April 18, 2001.

2.   Exercise of Warrant.

     (a) Except as provided in Section 4 below,  exercise of the purchase rights
     represented by this Warrant may be made in whole or in part, at any time or
     from time to time,  before the  Expiration  Date,  or such  earlier date on
     which  this  Warrant,  by the  surrender  of this  Warrant  and a Notice of
     Exercise,  in the form attached hereto as Exhibit A, duly executed,  at the
     office of the Company (or such other  office or agency of the Company as it
     may designate by notice in writing to the  registered  holder hereof at the
     address of such  holder  appearing  in the books of the  Company)  and upon
     payment of an amount of consideration  therefor equal to the Exercise Price
     multiplied by the number of shares of Common Stock thereby purchased,  such
     consideration  payable by  certified  check or  cashier's  check or by wire
     transfer of immediately available funds to a bank account designated by the
     Company.

                                                                      Page No. 1


     (b) In the event of an exercise  of this  Warrant in  accordance  with this
     Section 2, the Holder  shall be entitled to receive a  certificate  for the
     number of shares of Common Stock so purchased.  Certificates for the shares
     of Common Stock purchased hereunder shall be delivered to the Holder hereof
     within five (5) business  days after the date on which this  Warrant  shall
     have been exercised as aforesaid.

3.   Reservation  of Shares.  The  Company  hereby  covenants  that at all times
     during the term of this Warrant there shall be reserved a sufficient number
     of  shares of its  Common  Stock as shall be  required  for  issuance  upon
     exercise of this Warrant.

4.   No Fractional Shares or Scrip. No fractional  shares or scrip  representing
     fractional shares shall be issued upon the exercise of this Warrant.

5.   Loss,  Theft,  Destruction  or Mutilation  of Warrant.  Upon receipt by the
     Company of evidence  satisfactory to it of the loss, theft,  destruction or
     mutilation of this Warrant, and (in the case of loss, theft or destruction)
     receipt of indemnification  reasonably satisfactory to the Company, and (in
     the case of mutilation)  upon surrender and  cancellation  of this Warrant,
     the  Company  will  execute and deliver to the Holder a new Warrant of like
     tenor and date and any such lost,  stolen,  destroyed or mutilated  Warrant
     shall thereupon become void.

6.   Rights of the Holder.  The Holder shall not, by virtue hereof,  be entitled
     to any rights of a stockholder in the Company, either at law or equity, and
     the rights of the Holder are limited to those expressed in this Warrant and
     are not  enforceable  against  the  Company  except to the extent set forth
     herein.

7.   Adjustments of Exercise Price and Number of Warrant Shares.  The number and
     kind of  securities  purchasable  upon the exercise of this Warrant and the
     Exercise  Price shall be subject to  adjustment  from time to time upon the
     happening of any of the following:

     in case the Company shall (i) declare or pay a dividend in shares of Common
     Stock or make a  distribution  in shares of Common  Stock to holders of its
     outstanding  Common Stock, (ii) subdivide its outstanding  shares of Common
     Stock,  (iii) combine its outstanding shares of Common Stock into a smaller
     number of shares of Common  Stock or (iv) issue any  shares of its  capital
     stock in a reclassification of the Common Stock, then the number of Warrant
     Shares purchasable upon exercise of this Warrant  immediately prior thereto
     shall be adjusted so that the Holder  shall be entitled to receive the kind
     and number of Warrant  Shares or other  securities  of the Company which he
     would have owned or have been  entitled  to receive had such  Warrant  been
     exercised in advance  thereof.  Upon each such  adjustment  of the kind and
     number of  Warrant  Shares or other  securities  of the  Company  which are
     purchasable hereunder,  the Holder shall thereafter be entitled to purchase
     the  number of  Warrant  Shares  or other  securities  resulting  from such
     adjustment at an Exercise  Price per such Warrant  Share or other  security
     obtained by multiplying the Exercise Price in effect  immediately  prior to
     such adjustment by the number of Warrant Shares purchasable pursuant hereto
     immediately  prior to such adjustment and dividing by the number of Warrant
     Shares or other securities of the Company resulting from such adjustment.

     An  adjustment  made  pursuant  to this  Section 7 shall  become  effective
     immediately  after the  effective  date of such  event  retroactive  to the
     record date, if any, for such event.



                                                                      Page No. 2


8.   Notice of  Adjustment.  Whenever the number of Warrant  Shares or number or
     kind of securities or other property  purchasable upon the exercise of this
     Warrant or the Exercise Price is adjusted as herein  provided,  the Company
     shall  promptly  mail by  registered  or  certified  mail,  return  receipt
     requested,  to the Holder notice of such adjustment or adjustments  setting
     forth the  number of Warrant  Shares  (and other  securities  or  property)
     purchasable  upon the exercise of this  Warrant and the  Exercise  Price of
     such  Warrant  Shares  (and  other   securities  or  property)  after  such
     adjustment,  setting forth a brief  statement of the facts  requiring  such
     adjustment and setting forth the  computation by which such  adjustment was
     made.

9.   Transfer to Comply with the Securities Act; Registration by Company.

     (a) Compliance  with  Securities  Laws. This Warrant and the Warrant Shares
     have not been registered  under the Securities Act of 1933, as amended (the
     "Act"), or under any applicable state or foreign  securities laws, and this
     Warrant has been issued to the Holder for investment  purposes only and not
     with a view to the  distribution  of either  this  Warrant  or the  Warrant
     Shares.  Neither  this  Warrant nor any of the Warrant  Shares or any other
     security  issued or issuable  upon  exercise  of this  Warrant may be sold,
     transferred,  assigned,  pledged,  hypothecated or otherwise disposed of in
     the  absence  of an  opinion,  in  form,  scope  and  substance  reasonably
     acceptable to the Company, of counsel reasonably  acceptable to the Company
     that registration is not required under the Act, or under the provisions of
     applicable  federal and state securities laws,  except that with respect to
     any  transfer of this Warrant or the Warrant  Shares or any other  security
     issued or issuable  upon  exercise of this  Warrant to an  affiliate of the
     Holder where the beneficial ownership of such security or securities by the
     Holder's ultimate parent has not changed, the counsel rendering the opinion
     may be in-house  legal  counsel to the Holder.  After  satisfaction  of the
     requirements of this Section 9(a), the Company shall  immediately  transfer
     this  Warrant on the books of the Company  and shall  execute and deliver a
     new  Warrant  of  like  tenor  to  the  appropriate  assignee(s)  expressly
     evidencing  the right to purchase the aggregate  number of shares of Common
     Stock purchasable hereunder or such portion of such number shares of Common
     Stock as shall be contemplated by any such assignment. Each certificate for
     the Warrant,  the Warrant Shares and any other security  issued or issuable
     upon  exercise of this Warrant  shall contain a legend on the face thereof,
     in form,  substance  and scope  satisfactory  to counsel  for the  Company,
     setting forth the restrictions on transfer contained in this Section 9(a).

     (b) Registration.  Within six (6) months from the date hereof,  the Company
     shall  file  a  registration  statement  under  the  Act  (a  "Registration
     Statement") with the Securities and Exchange  Commission (the "Commission")
     registering  for  re-offer  and  re-sale the Warrant  Shares  and/or  offer
     piggyback  registration  rights to the Holder  with  respect to the Warrant
     Shares under a Registration  Statement filed by the Company with respect to
     its Common Stock (other than another Registration  Statement on Form S-4 or
     Form S-8 or any successor thereto).  The Company shall use its best efforts
     to  cause  the  Registration  Statement  to be  declared  effective  by the
     Commission no later than the last day of such six (6) moth period. Once any
     such Registration  Statement is declared  effective by the Commission,  the
     Company  shall use its best efforts to keep the  Registration  Statement or
     Registration Statements, as applicable, effective and current until all the
     Warrant Shares registered  thereunder are sold or



                                                                      Page No. 3


     may be sold in any 90-day  period  without  registration  under Rule 144 or
     another appropriate  exemption under the Act. If no Registration  Statement
     is declared  effective by the Commission  within sixty (60) days of the end
     of such six (6) month period,  or if a  Registration  Statement is declared
     effective but after becoming  effective  becomes subject to a stop order or
     is not otherwise available for use by the Holder (other than as a result of
     the application of standard  black-out  periods) for a period of forty-five
     (45) days,  then  thereafter the Holder may demand on up to an aggregate of
     three (3) separate  occasions  that the Warrant  Shares be  registered on a
     registration statement filed with the Commission or have the Warrant Shares
     included  on any  other  applicable  Registration  Statement  filed  by the
     Company, which "demand" and "piggyback" registration rights will be subject
     to such reasonable terms as are ordinarily offered to investors  purchasing
     similar securities to this Warrant acquired in a similar manner,  until all
     the Warrant Shares are sold.

     (c)  Registration   Expenses.   All  fees  and  expenses  incident  to  the
     registration  of the Warrant  Shares shall be borne by the  Company,  other
     than fees and expenses of any counsel  retained by the Holder in connection
     with the  Registration  Statement,  which fees and expenses  shall be borne
     exclusively  by the Holder  whether or not the  registration  statement  is
     filed  or  becomes  effective  and the  Holder's  pro rata  payment  of any
     underwriter's  commission in the case of an underwritten offering. The fees
     and expenses to be borne by the Company shall include,  without limitation,
     the following:  (i) all registration  and filing fees  (including,  without
     limitation,  fees and expenses  (A) with respect to filings  required to be
     made with the Nasdaq and each other securities  exchange or market on which
     Warrant Shares are required hereunder to be listed, and (B) with respect to
     filings  required to be made with the  Commission;  (ii) printing  expenses
     (including,  without  limitation,  expenses  of printing  certificates  for
     Warrant Shares and of printing prospectuses if the printing of prospectuses
     is requested by the holders of a majority of the Warrant Shares included in
     the  registration  statement),  (iii)  messenger,  telephone  and  delivery
     expenses; and (iv) fees and disbursements of counsel for the Company.

     (d) Right to  Suspend  or  Abandon.  Subject to the rights of the Holder in
     Section 9(b) hereof,  nothing in this Section 9 shall create any  liability
     or  obligation  on the part of the  Company to the Holder if the Company in
     its  reasonable  discretion  should  decide (i) not to file a  registration
     statement  for which a notice of a  piggyback  registration  right has been
     sent to the Holder; (ii) to withdraw such registration statement subsequent
     to its  filing  and prior to the later of its  effectiveness  offering;  or
     (iii) to suspend or  terminate  any  offering or the  effectiveness  of any
     registration  statement  by the  Company or at the  request of any  person,
     entity or governmental authority.

     (e) With a view to making  available  the benefits of Rule 144  promulgated
     under the Act ("Rule 144"), which may permit the sale of the Warrant Shares
     to the public  without  registration  under the Act,  subject to compliance
     with the terms and  provisions  of the Act,  the Company  agrees to use its
     best efforts to:

               (i)    make and keep public information available, as those terms
                      are understood and defined in Rule 144;



                                                                      Page No. 4


               (ii)   file with the  Commission  in a timely  manner all reports
                      and other documents  required of the Company under the Act
                      and the  Securities  Exchange Act of 1934, as amended (the
                      "Exchange Act"); and

               (iii)  furnish to the  Holder,  so long as the Holder owns any of
                      the Warrant  Shares,  promptly  upon  receipt of a written
                      request from the Holder a written statement by the Company
                      as to its compliance  with the reporting  requirements  of
                      the Act and the  Exchange  Act, a copy of the most  recent
                      annual or quarterly  report of the Company  filed with the
                      Commission  under the Exchange Act, and such other reports
                      and documents of the Company and other  information in the
                      possession of or  reasonably  obtainable by the Company as
                      the Holder may  reasonably  request in availing  itself or
                      any rule or  regulation  of the  Commission  allowing  the
                      Holder to sell any such  securities  without  registration
                      under the Act.

10.  Indemnification and Contribution.

     (a)  Indemnification  By The Company.  The Company shall indemnify and hold
     harmless the Holder and the officers, directors, agents or employees of the
     Holder and each  person who  controls  the Holder  (within  the  meaning of
     Section 15 of the Act or Section 20 of the Exchange Act) and the respective
     present and former officers,  directors,  agents and employees of each such
     controlling person, to the fullest extent permitted by applicable law, from
     and against any and all claims, losses,  damages,  liabilities,  penalties,
     judgments,  costs (including,  without limitation,  costs of investigation)
     and expenses (including, without limitation,  attorneys' fees and expenses)
     (collectively,  "Losses"),  incurred  by any  of  them,  arising  out of or
     relating  to any  untrue or alleged  untrue  statement  of a material  fact
     contained in the  registration  statement,  any  prospectus  or any form of
     prospectus or in any amendment or supplement  thereto or in any preliminary
     prospectus,  or  arising  out of or  relating  to any  omission  or alleged
     omission of a material fact  required to be stated  therein or necessary to
     make  the  statements  therein  (in the case of any  prospectus  or form of
     prospectus or supplement  thereto,  in the light of the circumstances under
     which they were made) not misleading, except to the extent that such untrue
     statements  or omissions  are based upon  information  regarding the Holder
     furnished  in  writing  to the  Company  by the  Holder  expressly  for use
     therein,  which information was reasonably relied on by the Company for use
     therein.

     (b)  Indemnification  By The Holder.  The Holder shall  indemnify  and hold
     harmless the Company, the directors,  officers, agents and employees of the
     Company,  and each person who controls  the Company  (within the meaning of
     Section  15 of the  Act  and  Section  20 of the  Exchange  Act),  and  the
     respective present and former directors,  officers,  agents or employees of
     such  controlling  persons,  to the fullest extent  permitted by applicable
     law,  from and against all Losses,  as incurred,  arising  solely out of or
     based solely upon any untrue  statement of a material fact contained in the
     registration  statement,  any  prospectus,  or any



                                                                      Page No. 5


     form of  prospectus,  or  arising  solely out of or based  solely  upon any
     omission of a material fact  required to be stated  therein or necessary to
     make  the  statements  therein  (in the case of any  prospectus  or form of
     prospectus or supplement  thereto,  in the light of the circumstances under
     which  they  were  made) not  misleading,  to the  extent,  but only to the
     extent,  that such untrue  statement or omission is contained in or omitted
     from any  information  so furnished in writing by the Holder to the Company
     specifically for inclusion in the registration statement or such prospectus
     and that such information was reasonably relied upon by the Company for use
     in the registration statement,  such prospectus or such form of prospectus;
     provided that the maximum amount of the indemnification  payments by Holder
     shall not exceed the net sale proceeds of any of the shares of Common Stock
     sold by Holder pursuant to the registration statement.

     (c) Conduct of Indemnification  Proceedings.  If any action,  suit or other
     proceeding (a "Proceeding") shall be brought or asserted against any person
     entitled to indemnity hereunder (an "Indemnified  Party"), such Indemnified
     Party  promptly  shall notify the person from whom  indemnity  hereunder is
     sought (the  "Indemnifying  Party") in writing,  and the Indemnifying Party
     shall  assume the  defense  thereof,  including,  without  limitation,  the
     employment of counsel reasonably  satisfactory to the Indemnified Party and
     the payment of all fees and expenses  incurred in  connection  with defense
     thereof;  provided that the failure of any  Indemnified  Party to give such
     notice  shall not  relieve the  Indemnifying  Party of its  obligations  or
     liabilities  pursuant to this Section 10, except, to the extent,  that such
     failure  shall  have  adversely   prejudiced  the  Indemnifying  Party.  An
     Indemnified  Party shall have the right to employ  separate  counsel in any
     such Proceeding and to participate in the defense thereof, but the fees and
     expenses of such counsel shall be at the expense of such Indemnified  Party
     or Parties unless:  (1) the Indemnifying Party has agreed in writing to pay
     such fees and  expenses;  or (2) the  Indemnifying  Party shall have failed
     promptly to assume the  defense of such  Proceeding  and to employ  counsel
     reasonably  satisfactory to such Indemnified  Party in any such Proceeding;
     or (3) the named parties to any such  Proceeding  (including  any impleaded
     parties)  include both such Indemnified  Party and the Indemnifying  Party,
     and such  Indemnified  Party  shall have been  advised  by  counsel  that a
     conflict  of  interest  is  likely  to exist if the  same  counsel  were to
     represent such Indemnified Party and the Indemnifying Party (in which case,
     if such Indemnified  Party notifies the Indemnifying  Party in writing that
     it elects to employ  separate  counsel at the  expense of the  Indemnifying
     Party,  the  Indemnifying  Party  shall not have the  right to  assume  the
     defense   thereof  and  such  counsel  shall  be  at  the  expense  of  the
     Indemnifying  Party).  The  Indemnifying  Party shall not be liable for any
     settlement of any such  Proceeding  effected  without its written  consent,
     which consent shall not be unreasonably  withheld.  No  Indemnifying  Party
     shall,  without the prior written consent of the Indemnified Party,  effect
     any  settlement  of  any  pending   Proceeding  in  respect  of  which  any
     Indemnified  Party  is  a  party,   unless  such  settlement   includes  an
     unconditional  release  of such  Indemnified  Party from all  liability  on
     claims  that  are the  subject  matter  of such  Proceeding.  All  fees and
     expenses of the Indemnified  Party (including  reasonable fees and expenses
     to the extent  incurred in connection  with  investigating  or preparing to
     defend such  Proceeding  in a manner not  inconsistent  with this  Section)
     shall be paid to the  Indemnified  Party,  as incurred,  within thirty (30)
     business  days  of  written  notice  thereof  to  the  Indemnifying  Party,
     regardless of whether it is ultimately determined that an Indemnified Party
     is  not  entitled  to   indemnification   hereunder;   provided



                                                                      Page No. 6


     that the Indemnifying Party may require such Indemnified Party to undertake
     to  reimburse  all such  fees and  expenses  to the  extent  it is  finally
     judicially  determined  that  such  Indemnified  Party is not  entitled  to
     indemnification hereunder.

     (d)  Contribution.  If a claim for  indemnification  under Section 10(a) or
     10(b) is  unavailable  to an  Indemnified  Party  because  of a failure  or
     refusal of a  governmental  authority  to enforce such  indemnification  in
     accordance  with its terms (by reason of public policy or otherwise),  then
     the Indemnifying  Party, in lieu of indemnifying  such  Indemnified  Party,
     shall contribute to the amount paid or payable by the Indemnified  Party as
     a result of such Losses,  in such  proportion as is  appropriate to reflect
     the  relative  fault of the  Indemnifying  Party and  Indemnified  Party in
     connection with the actions,  statements or omissions that resulted in such
     Losses,  as  well  as any  other  relevant  equitable  considerations.  The
     relative fault of such  Indemnifying  Party and Indemnified  Party shall be
     determined  by  reference  to,  among other  things,  whether any action in
     question,  including any untrue or alleged  untrue  statement of a material
     fact or omission or alleged  omission of a material fact, has been taken or
     made by, or relates to information supplied by, the Indemnifying,  Party or
     the Indemnified Party, and the parties' relative intent, knowledge,  access
     to information and opportunity to correct or prevent such action, statement
     or omission.  The payment  obligations of Holder hereunder shall be limited
     to the net sale  proceeds  of any of the  shares  of Common  Stock  sold by
     Holder pursuant to the Registration Statement.

     (e)  Equitable  Considerations.  The Company  and the Holder  agree that it
     would not be just and equitable if  contribution  pursuant to Section 10(d)
     were determined by pro rata allocation or by any other method of allocation
     which does not take into account the equitable  considerations  referred to
     in Section 10(d).  The indemnity and contribution  agreements  contained in
     this  Section 10 are in addition  to any  liability  that the  Indemnifying
     Parties may have to the Indemnified Parties.

11.  Notice. Any notice or other  communication  required or permitted hereunder
     shall be in writing and shall be  delivered  personally,  sent by facsimile
     transmission  or sent by certified,  registered  or express  mail,  postage
     pre-paid.  Any  such  notice  shall  be  deemed  given  when  so  delivered
     personally  or if sent by  facsimile  transmission,  on a business day (for
     which  a   mechanically   generated   receipt   evidencing   the   time  of
     transmission),  or, if mailed,  three (3) days after the date of deposit in
     the United States mails.  The addresses for such notices or  communications
     shall be with  respect to the Holder of this  Warrant or of Warrant  Shares
     issued pursuant hereto:

                     Texas Instruments Incorporated
                     7839 Churchill Way
                     Mail Station 3995
                     Dallas, TX  75251
                     Facsimile no.: (972)-917-3804
                     ATT: Charles D. Tobin



                                                                      Page No. 7


           with a copy to:

                     Texas Instruments Incorporated
                     12500 TI Boulevard
                     Mail Station 8658
                     Dallas, TX  75243
                     Facsimile no.:  (214) 917-4418
                     ATT: Joseph F. Hubach

or with respect to the Company, addressed to:

                     Xybernaut Corporation
                     12701 Fair Lakes Circle
                     Suite 550
                     Fairfax, Virginia 22033
                     Facsimile no.: (703) 631-3903
                     ATT: John F. Moynahan
                     Chief Financial Officer

           With a copy to:

                     Martin Eric Weisberg, Esq.
                     Jenkens & Gilchrist Parker Chapin LLP
                     The Chrysler Building
                     405 Lexington Avenue
                     New York, New York 10174
                     Facsimile no.: (212) 704-6288

or to such other  address or  addresses  or  facsimile  number or numbers as the
Holder or the Company,  as the case may be, may most recently have designated in
writing  to the  other  party  hereto by notice  given in  accordance  with this
Section 11.

12.  Supplements and Amendments; Whole Agreement. This Warrant may be amended or
     supplemented only by an instrument in writing signed by the Company and the
     Holder.  This Warrant contains the full  understanding and agreement of the
     parties  hereto with respect to the subject  matter  hereof and thereof and
     there are no  representations,  warranties,  agreements  or  understandings
     other than expressly contained herein and therein.

13.  Governing Law. This Warrant shall be deemed to be a contract made under the
     laws of the State of Delaware and for all purposes shall be governed by and
     construed in accordance with the laws of such State applicable to contracts
     to be made and performed entirely within such State.

14.  Counterparts.  This  Warrant may be executed in any number of  counterparts
     and each of such  counterparts  shall for all  purposes  be deemed to be an
     original,  and all such counterparts shall together  constitute but one and
     the same instrument.



                                                                      Page No. 8


15.  Descriptive Headings.  Descriptive headings of the several sections of this
     Warrant are inserted for  convenience  only and shall not control or affect
     the meaning or construction of any of the provisions hereof.


                           [INTENTIONALLY LEFT BLANK]






                                                                      Page No. 9



      IN WITNESS WHEREOF, the parties hereto have executed this Warrant as of
April 18, 2001.


                                XYBERNAUT CORPORATION




                                By:
                                   -----------------------------------------
                                   Name: Edward G. Newman
                                   Title:   Chairman and CEO



                                                                     Page No. 10


                                                                       EXHIBIT A

                          NOTICE OF EXERCISE OF WARRANT


          The  undersigned  hereby  irrevocably  elects to  exercise  the right,
represented by Warrant  Certificate No. W____, dated as of __________,  2001, to
purchase  __________  shares of the Common Stock,  par value $0.01 per share, of
Xybernaut Corporation,  a Delaware corporation,  and tenders herewith payment in
accordance with Section 2 of said Warrant.

          In  exercising  the  Warrant,  the  undersigned  hereby  confirms  and
acknowledges  that the shares of Common Stock are being acquired  solely for the
account of the  undersigned  and not as a nominee for any other  party,  and for
investment, and that the undersigned will not offer sell or otherwise dispose of
any such shares of Common Stock, except under circumstances that will not result
in a violation of the United States  Securities Act of 1933, as amended,  or any
foreign or state securities laws.

          Please issue a certificate or certificates representing said shares of
Common  Stock  in the  name  of the  undersigned  or in  such  other  name as is
specified below,  and please issue a new Warrant for the unexercised  portion of
the attached Warrant in such name, if applicable:

                -----------------------------------------------
                (Name)

                -----------------------------------------------
                (Address)
                -----------------------------------------------





Dated:
      ---------------------





                                        ----------------------------------
                                        Name:



                                                                     Page No. 11




Form to be used to assign Warrant:

                                   ASSIGNMENT

          (To be executed by the  registered  Holder to effect a transfer of the
within Purchase Option):

          FOR VALUE RECEIVED,  _____________________________________ does hereby
sell,  assign and  transfer  unto the right to  purchase  ______________________
shares of  Common  Stock to  purchase  _____________  shares of Common  Stock of
Xybernaut  Corporation,  a Delaware  corporation  ("Company"),  evidenced by the
within  Warrant and does hereby  authorize the Company to transfer such right on
the books of the Company.

Dated: _____________________, 20___




                                      ------------------------------------
                                      Signature




                                                                     Page No. 12