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                         PATRIOT SCIENTIFIC CORPORATION




                                   FORM 10-KSB
                                  Annual Report



                                EXHIBIT NO. 4.13


                    Form of Warrant to Purchase Common Stock


                                     EX-66
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THIS WARRANT AND THE SECURITIES RECEIVABLE UPON EXERCISE HEREOF HAVE NOT BEEN
REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"),
OR ANY STATE SECURITIES LAW, AND MAY NOT BE SOLD, TRANSFERRED, PLEDGED,
HYPOTHECATED OR OTHERWISE DISPOSED OF UNLESS (i) A REGISTRATION STATEMENT UNDER
THE SECURITIES ACT AND APPLICABLE STATE SECURITIES LAWS SHALL HAVE BECOME
EFFECTIVE WITH REGARD THERETO, OR (ii) AN EXEMPTION FROM REGISTRATION UNDER THE
SECURITIES ACT AND APPLICABLE STATE SECURITIES LAWS IS AVAILABLE IN CONNECTION
WITH SUCH OFFER, SALE OR TRANSFER.

Warrant to Purchase
100,000 shares


                        WARRANT TO PURCHASE COMMON STOCK
                                       OF
                         PATRIOT SCIENTIFIC CORPORATION

        THIS CERTIFIES that SPELLCASTER TELECOMMUNICATIONS, INC. or any
subsequent ("Holder") hereof, has the right to purchase from PATRIOT SCIENTIFIC
CORPORATION, a Delaware corporation (the "Company"), not more than 100,000 fully
paid and nonassessable shares of the Company's Common Stock, par value $.00001
per share ("Common Stock"), at a price equal to the Exercise Price as defined in
Section 3 below, subject to adjustment as provided herein, at any time on or
before 5:00 p.m., San Diego, California time, on April 29, 2000.


        The Holder of this Warrant agrees with the Company that this Warrant is
issued and all rights hereunder shall be held subject to all of the conditions,
limitations and provisions set forth herein.

        1.     Date of Issuance.

        This Warrant shall be deemed to be issued on April 28, 1998 ("Date of
Issuance").

        2.     Exercise.

        (a) Manner of Exercise. This Warrant may be exercised as to all or any
lesser number of full shares of Common Stock covered hereby upon surrender of
this Warrant, with the Exercise Form attached hereto duly executed, together
with the full Exercise Price (as defined in Section 3) for each share of Common
Stock as to which this Warrant is exercised, at the office of the Company,
Patriot Scientific Corporation, 10989 Via Frontera, San Diego, California 92127,
Attention: President, Telephone No. 619-674-5000, Telecopy No. 619-674-5005, or
at such other office or agency as the Company may designate in writing, by
overnight mail, with an advance copy of the Exercise Form attached as Exhibit A
("Exercise Form") by facsimile (such surrender and payment of the Exercise Price
hereinafter called the "Exercise of this Warrant").


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        (b) Date of Exercise. The "Date of Exercise" of the Warrant shall be
defined as the date that the advance copy of the Exercise Form is sent by
facsimile to the Company, provided that the original Warrant and Exercise Form
are received by the Company within five (5) business days thereafter. The
original Warrant and Exercise Form must be received within five (5) business
days of the Date of Exercise, or the exercise may, at the Company's option, be
considered void. Alternatively, the Date of Exercise shall be defined as the
date the original Exercise Form is received by the Company, if Holder has not
sent advance notice by facsimile.

        (c) Cancellation of Warrant. This Warrant shall be canceled upon its
Exercise, and, as soon as practical after the Date of Exercise, the Holder
hereof shall be entitled to receive Common Stock for the number of shares
purchased upon such Exercise, and if this Warrant is not exercised in full, the
Holder shall be entitled to receive a new Warrant or Warrants (containing terms
identical to this Warrant) representing any unexercised portion of this Warrant
in addition to such Common Stock.

        (d) Holder of Record. Each person in whose name any Warrant for shares
of Common Stock is issued shall, for all purposes, be deemed to have become the
Holder of record of such shares on the Date of Exercise of this Warrant,
irrespective of the date of delivery of such shares of Common Stock. Nothing in
this Warrant shall be construed as conferring upon the Holder hereof any rights
as a shareholder of the Company.

        3.     Payment of Warrant Exercise Price.

        The Exercise Price ("Exercise Price") shall equal $ 1.25.

        Payment of the Exercise Price may be made by cash, certified or cashiers
check, or wire transfer.

        For purposes of Rule 144 and sub-section (d)(3)(ii) thereof, it is
intended, understood and acknowledged that the Common Stock issuable upon
exercise of this Warrant shall be deemed to have been acquired at the time this
Warrant was exercised. Moreover, it is intended, understood and acknowledged
that the holding period for the Common Stock issuable upon exercise of this
Warrant shall be deemed to have commenced on the date this Warrant was
exercised.


        4.     Transfer Rights

        Subject to the provisions of Section 8 of this Warrant, this Warrant may
be transferred on the books of the Company, in whole or in part, in person or by
attorney, upon surrender of this Warrant properly endorsed. This Warrant shall
be canceled upon such surrender and, as soon as practicable thereafter, the
person to whom such transfer is made shall be entitled to receive a new Warrant
or Warrants as to the portion of this Warrant transferred, and the Holder of
this Warrant shall be entitled to receive a new Warrant or Warrants as to the
portion hereof retained.

        5.     Anti-Dilution Adjustments.


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        (a) Stock Dividend. If the Company shall at any time declare a dividend
payable in shares of Common Stock, then the Holder hereof, upon Exercise of this
Warrant after the record date for the determination of Holders of Common Stock
entitled to receive such dividend, shall be entitled to receive upon Exercise of
this Warrant, in addition to the number of shares of Common Stock as to which
this Warrant is Exercised, such additional shares of Common Stock as such Holder
would have received had this Warrant been Exercised immediately prior to such
record date and the Exercise Price will be proportionately adjusted.

        (b) Recapitalization or Reclassification. If the Company shall at any
time effect a recapitalization, reclassification or other similar transaction of
such character that the shares of Common Stock shall be changed into or become
exchangeable for a larger or smaller number of shares, then upon the effective
date thereof, the number of shares of Common Stock which the Holder hereof shall
be entitled to purchase upon Exercise of this Warrant shall be increased or
decreased, as the case may be, in direct proportion to the increase or decrease
in the number of shares of Common Stock by reason of such recapitalization,
reclassification or similar transaction, and the Exercise Price shall be, in the
case of an increase in the number of shares, proportionally decreased and, in
the case of decrease in the number of shares, proportionally increased. The
Company shall give the Warrant Holder the same notice it provides to holders of
Common Stock of any transaction described in this Section 5(b).

        (c) Distributions. If the Company shall at any time distribute to
Holders of Common Stock cash, evidences of indebtedness or other securities or
assets (other than cash dividends or distributions payable out of earned surplus
or net profits for the current or preceding year) then, in any such case, the
Holder of this Warrant shall be entitled to receive, upon exercise of this
Warrant, with respect to each share of Common Stock issuable upon such Exercise,
the amount of cash or evidences of indebtedness or other securities or assets
which such Holder would have been entitled to receive with respect to each such
share of Common Stock as a result of the happening of such event had this
Warrant been Exercised immediately prior to the record date or other date fixing
shareholders to be affected by such event (the "Determination Date") or, in lieu
thereof, if the Board of Directors of the Company should so determine at the
time of such distribution, a reduced Exercise Price determined by multiplying
the Exercise Price on the Determination Date by a fraction, the numerator of
which is the result of such Exercise Price reduced by the value of such
distribution applicable to one share of Common Stock (such value to be
determined by the Board in its discretion) and the denominator of which is such
Exercise Price.

        (d) Notice of Consolidation or Merger. In the event of a merger,
consolidation, exchange of shares, recapitalization, reorganization, or other
similar event, as a result of which shares of Common Stock of the Company shall
be changed into the same or a different number of shares of the same or another
class or classes of stock or securities or other assets of the Company or
another entity or there is a sale of all or substantially all the Company's
assets (a "Corporate Change"), then this Warrant shall be assumed by the
acquiring entity or any affiliate thereof and thereafter this Warrant shall be
exerciseable into such class and type of securities or other assets as the
Holder would have received had the Holder exercised this Warrant immediately
prior to such Corporate Change; provided, however, that Company may not affect
any Corporate Change unless it first shall have given thirty (30) business days
notice to the Holder hereof of any Corporate Change.


                                     EX-69
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        (e)    Exercise Price Adjusted. As used in this Warrant, the term 
"Exercise Price" shall mean the purchase price per share specified in Section 3
of this Warrant, as it may be adjusted from time to time, until the occurrence
of an event stated in subsection (a), (b) or (c) of this Section 5 and
thereafter shall mean said price as adjusted from time to time in accordance
with the provisions of said subsection. No such adjustment under this Section 5
shall be made unless such adjustment would change the Exercise Price at the time
by $.01 or more; provided, however, that all adjustments not so made shall be
deferred and made when the aggregate thereof would change the Exercise Price at
the time by $.01 or more. No adjustment made pursuant to any provision of this
Section 5 shall have the effect of increasing the total consideration payable
upon Exercise of this Warrant in respect of all the Common Stock as to which
this Warrant may be exercised. Notwithstanding anything to the contrary
contained herein, the Exercise Price shall not be reduced to an amount below the
par value of the Common Stock.

        (f)    Adjustments: Additional Shares, Securities or Assets. In the 
event that at any time, as a result of an adjustment made pursuant to this
Section 5, the Holder of this Warrant shall, upon Exercise of this Warrant,
become entitled to receive shares and/or other securities or assets (other than
Common Stock) then, wherever appropriate, all references herein to shares of
Common Stock shall be deemed to refer to and include such shares and/or other
securities or assets; and thereafter the number of such shares and/or other
securities or assets shall be subject to adjustment from time to time in a
manner and upon terms as nearly equivalent as practicable to the provisions of
this Section 5.

        6.     Fractional Interests.

               No fractional shares or scrip representing fractional shares
shall be issuable upon the Exercise of this Warrant, but on Exercise of this
Warrant, the Holder hereof may purchase only a whole number of shares of Common
Stock. If, on Exercise of this Warrant, the Holder hereof would be entitled to a
fractional share of Common Stock or a right to acquire a fractional share of
Common Stock, such fractional share shall be disregarded and the number of
shares of Common Stock issuable upon conversion shall be the next higher number
of shares.

        7.     Reservation of Shares.

               The Company shall at all times reserve for issuance such number
of authorized and unissued shares of Common Stock (or other securities
substituted therefor as herein above provided) as shall be sufficient for
Exercise and payment of the Exercise Price of this Warrant. The Company
covenants and agrees that upon Exercise of this Warrant, all shares of Common
Stock issuable upon such Exercise shall be duly and validly issued, fully paid,
nonassessable and not subject to preemptive rights, rights of first refusal or
similar rights of any person or entity.

        8.     Restrictions on Transfer.

               (a) Registration or Exemption Required. This Warrant and the
Common Stock issuable on Exercise hereof have not been registered under the
Securities Act of 1933, as amended, and may not be sold, transferred, pledged,
hypothecated or otherwise disposed of in the absence of registration or the
availability of an exemption from registration under said Act. All shares of
Common 


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Stock issued upon Exercise of this Warrant shall bear an appropriate legend to
such effect, if applicable.

               (b) Assignment. Assuming the conditions of (a) above regarding
registration or exemption have been satisfied, the Holder may sell, transfer,
assign, pledge or otherwise dispose of this Warrant, in whole or in part. Holder
shall deliver a written notice to Company, substantially in the form of the
Assignment attached hereto as Exhibit B, indicating the person or persons to
whom the Warrant shall be assigned and the respective number of warrants to be
assigned to each assignee. The Company shall effect the assignment within ten
days, and shall deliver to the assignee(s) designated by Holder a Warrant or
Warrants of like tenor and terms for the appropriate number of shares.

               (c) Investment Intent. The Warrant and Common Stock issuable upon
conversion are intended to be held for investment purposes and not with an
intent to distribution, as defined in the Act.

        9.     Benefits of this Warrant.

               Nothing in this Warrant shall be construed to confer upon any
person other than the Company and the Holder of this Warrant any legal or
equitable right, remedy or claim under this Warrant and this Warrant shall be
for the sole and exclusive benefit of the Company and the Holder of this
Warrant.

        10.    Applicable Law.

               This Warrant is issued under and shall for all purposes be
governed by and construed in accordance with the laws of the state of
California, without giving effect to conflict of law provisions thereof.

        11.    Loss of Warrant.

               Upon receipt by the Company of evidence of the loss, theft,
destruction or mutilation of this Warrant, and (in the case of loss, theft or
destruction) of indemnity or security reasonably satisfactory to the Company,
and upon surrender and cancellation of this Warrant, if mutilated, the Company
shall execute and deliver a new Warrant of like tenor and date.

        12.    Notice or Demands.

Notices or demands pursuant to this Warrant to be given or made by the Holder of
this Warrant to or on the Company shall be sufficiently given or made if sent by
certified or registered mail, return receipt requested, postage prepaid, and
addressed, until another address is designated in writing by the Company,
Patriot Scientific Corporation, 10989 Via Frontera, San Diego, California 92127,
Attention: President, Telephone No. 619-674-5000, Telecopy No. 619-674-5005.
Notices or demands pursuant to this Warrant to be given or made by the Company
to or on the Holder of this Warrant shall be sufficiently given or made if sent
by certified or registered mail, return receipt requested, postage prepaid, and
addressed, Attn: Holder, address: Spellcaster Telecommunications Inc., 73 Laird
Dr., Suite 206, Toronto, Ontario, Canada M4G-3T4, Attention: President.
Telephone 


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No. 416-425-0600, Telecopy No. 416-425-0854, until another address is designated
in writing by Holder.


IN WITNESS WHEREOF, the undersigned has executed this Warrant as of the 28th day
of April, 1998.

                         PATRIOT SCIENTIFIC CORPORATION

                                     By:  ________________________________
                                     Lowell W. Giffhorn
                                     Chief Financial Officer


                                     EX-72
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                                    EXHIBIT A

                                  EXERCISE FORM

                            TO: ___________________.

        The undersigned hereby irrevocably exercises the right to purchase
____________ of the shares of Common Stock of PATRIOT SCIENTIFIC CORPORATION, a
__________ corporation, evidenced by the attached Warrant, and herewith makes
payment of the Exercise Price with respect to such shares in full, all in
accordance with the conditions and provisions of said Warrant.

        The undersigned agrees not to offer, sell, transfer or otherwise dispose
of any of such Common Stock, except in accordance with the provisions of Section
8 of the Warrant, and consents that the following legend may be affixed to the
stock certificates for the Common Stock hereby subscribed for, if such legend is
applicable:

        "The securities represented hereby have not been registered under the
        Securities Act of 1933, as amended (the "Securities Act"), or any
        provincial or state securities law, and may not be sold, transferred,
        pledged, hypothecated or otherwise disposed of until either (i) a
        registration statement under the Securities Act and applicable
        provincial or state securities laws shall have become effective with
        regard thereto, or (ii) an exemption from registration under the
        Securities Act or applicable provincial or state securities laws is
        available in connection with such offer, sale or transfer."

        The undersigned requests that stock certificates for such shares be
issued, and a warrant representing any unexercised portion hereof be issued,
pursuant to the Warrant in the name of the Registered Holder and delivered to
the undersigned at the address set forth below:


Dated:

------------------------------------------------------------------------
                         Signature of Registered Holder

------------------------------------------------------------------------
                        Name of Registered Holder (Print)


------------------------------------------------------------------------
                                     Address
------------------------------------------------------------------------

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                                    EXHIBIT B

                                   ASSIGNMENT

                    (To be executed by the registered Holder
                        desiring to transfer the Warrant)

FOR VALUE RECEIVED, the undersigned Holder of the attached Warrant hereby sells,
assigns and transfers unto the person or persons below named the right to
purchase _______ shares of the Common Stock of PATRIOT SCIENTIFIC CORPORATION
evidenced by the attached Warrant and does hereby irrevocably constitute and
appoint _______________________ attorney to transfer the said Warrant on the
books of the Company, with full power of substitution in the premises.

Dated:                                            ______________________________
                                                            Signature


Fill in for new Registration of Warrant:

-----------------------------------
               Name

-----------------------------------
               Address

-----------------------------------
Please print name and address of assignee
(including zip code number)

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NOTICE

The signature to the foregoing Exercise Form or Assignment must correspond to
the name as written upon the face of the attached Warrant in every particular,
without alteration or enlargement or any change whatsoever.


                                     EX-74