Document:

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                                                                   EXHIBIT 10.20

September 24, 1999

Mr. Jim Rollans
President and Chief Executive Officer
Fluor Signature Services

Dear Jim,

It is my pleasure to inform you that at the December 1998 Organization and
Compensation Committee meeting, the Board of Directors of Fluor Corporation (the
"Company") selected you to participate in a Retention Program. The amount of the
retention award was $2,750,000. At your request the award has been structured as
follows:

AWARD AMOUNT:                  $2,750,000

RETENTION PERIOD:              October 1, 1998 through October 31, 2001

RETENTION AGREEMENT:           The Award Amount is divided between the following
                               two components:

                               HOUSING

                               You have previously been provided with a personal
                               loan of $1,627,576 secured by a deed of trust on
                               your residence. The loan provides for an interest
                               rate of 4.52%, compounded annually with a balloon
                               payment of the entire amount due on termination
                               of employment. The loan presently states that it
                               is subject to acceleration in the event of your
                               termination of employment for any reason prior to
                               October 31, 2001. The Company will forgive the
                               loan including accrued interest in its entirety
                               (a) if you remain continuously employed by the
                               Company until October 31, 2001, or (b) if your
                               employment terminates prior to that date due to
                               (i) death, (ii) permanent and total disability,
                               (iii) a Company-initiated termination for any
                               reason other than for-cause or (iv) following a
                               Change of Control. If your employment with the
                               Company terminates for

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Jim Rollans
September 24, 1999
Page 2

                               any other reason prior to October 31, 2001
                               (including, without limitation, your voluntary
                               termination or a termination for cause) then this
                               loan shall remain in effect in accordance with
                               its terms.

                               For purposes hereof, the term "Change of Control"
                               shall be deemed to have occurred if, (a) a third
                               person, including a "group" as defined in Section
                               13(d)(3) of the Securities Exchange Act of 1934,
                               acquires shares of the Company having 25% or more
                               of the votes that may be cast for the election of
                               directors of the Company or (b) as a result of
                               any cash tender or exchange offer, merger or
                               other business combination, or any combination of
                               the preceding (a "transaction"), the persons who
                               are the directors of the Company before the
                               transaction shall cease to constitute a majority
                               of the Board of Directors of the Company or any
                               successor thereto.

                               ACCRUAL TO EXECUTIVE DEFERRAL COMPENSATION
                               PROGRAM ("EDCP")

                               You may earn $1,122,424, said amount to be
                               adjusted as provided below, if you remain
                               continuously employed by the Company until on or
                               after October 31, 2001 (the "EDCP Accrual").
                               During the period from October 1, 1998 to the
                               date upon which the EDCP Accrual vests (if at
                               all), you will also be entitled to invest the
                               EDCP Accrual by selecting one or more of the
                               crediting options contained in the EDCP.
                               Thereafter, the amount of your EDCP Accrual, if
                               vested, shall be adjusted based upon the
                               investment return that you would have otherwise
                               received had the EDCP Accrual been actually
                               earned as of October 1, 1998 and credited in your
                               EDCP account based upon your chosen crediting
                               option through the date of vesting. If no
                               crediting option is indicated, the EDCP Accrual
                               will be automatically credited as if you chose
                               the Money Market crediting option under the EDCP.

                               The EDCP Accrual, as adjusted, will vest and be
                               credited to your existing Company EDCP account
                               (a) if you remain

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Jim Rollans
September 24, 1999
Page 3

                               continuously employed by the Company until
                               October 31, 2001 or (b) if your employment
                               terminates prior to that date due to (i) death,
                               (ii) permanent and total disability, (iii) a
                               Company-initiated termination other than on a
                               for-cause basis or (iv) following a Change of
                               Control. If in the event your employment
                               terminates for any reason prior to any such
                               vesting date for any other reason (including,
                               without limitation, your voluntary termination or
                               a termination for cause), then the EDCP Accrual,
                               as adjusted, will be forfeited.

Please indicate your acknowledgment of the terms of the letter by signing in the
space provided and returning the original to me for your employee records. You
should also retain a copy for your file.

If you should have any questions, please give me a call at (949) 349-5435.

Sincerely,

Philip J. Carroll

AGREED BY:                                  AGREED BY:

/s/ P. J. CARROLL        9-24-99            /s/ J. O. ROLLANS        9-24-99
------------------------------------        ------------------------------------
PHILIP J. CARROLL          DATE             JAMES O. ROLLANS           DATE<PAGE>   1

                                                                     EXHIBIT 4.3

                           WESTERN DIGITAL CORPORATION
                       1993 EMPLOYEE STOCK PURCHASE PLAN,
                         AS AMENDED ON NOVEMBER 18, 1999

<PAGE>   2

                           WESTERN DIGITAL CORPORATION
                        1993 EMPLOYEE STOCK PURCHASE PLAN
--------------------------------------------------------------------------------

         The Western Digital Corporation 1993 Employee Stock Purchase Plan (the
"Plan") shall be established and operated in accordance with the following terms
and provisions.

         1. Definitions.

         As used in the Plan the following terms shall have the meanings set
forth below:

         (a) "Board" means the Board of Directors of the Company.

         (b) "Code" means the Internal Revenue Code of 1986, as amended.

         (c) "Committee" means the committee appointed by the Board to
administer the Plan as described in Section 4 below.

         (d) "Common Stock" means the Common Stock, $0.01 par value, of the
Company.

         (e) "Company" means Western Digital Corporation, a Delaware
corporation.

         (f) "Continuous Employment" means the absence of any interruption or
termination of service as an Employee with the Company and/or its Participating
Subsidiaries. Continuous Employment shall not be considered interrupted in the
case of a leave of absence agreed to in writing by the Company, provided that
such leave is for a period of not more than 90 days or reemployment upon the
expiration of such leave is guaranteed by contract or statute.

         (g) "Eligible Compensation" means, with respect to each Participant for
each pay period, the full salary and wages paid to such Participant by the
Company or a Participating Subsidiary, including commissions, bonuses (to the
extent not excluded below), overtime pay and shift differentials. Except as
otherwise determined by the Committee, "Eligible Compensation" does not include

                  (i) any amounts contributed by the Company or a Participating
Subsidiary to any pension plan or plan of deferred compensation,

                  (ii) any automobile or relocation allowances (or reimbursement
for any such expenses),

                  (iii) any amounts paid as a starting bonus or finder's fee,

                  (iv) any amounts realized from the exercise of qualified or
non-qualified stock options, or

                  (v) any amounts paid by the Company or a Participating
Subsidiary for other fringe benefits, such as health and welfare,
hospitalization and group life insurance benefits, or perquisites, or paid in
lieu of such benefits, such as cash-out of credits generated under a plan
qualified under Code Section 125.

         (h) "Eligible Employee" means an Employee who is

                  (i) customarily employed for at least twenty (20) hours per
week and more than five months in a calendar year, and

                  (ii) eligible to participate in the Plan as described in
Section 5 below.

                  If such person is (a) an Employee due to any classification or
reclassification of the person as an employee or common-law employee of the
Company or one of its Participating Subsidiaries by reason of action taken by
any tax or other governmental authority, or (b) an Employee who has a written
employment agreement providing that the Employee shall not participate in the
Plan until after two (2) years of Continuous Employment, then such Employee must
be employed for more than two (2) years by the Company or one of its
Participating Subsidiaries as well as meet the criteria set forth above in
subsections (i) and (ii) in order to be an Eligible Employee.

<PAGE>   3

         (i) "Employee" means each person currently employed by the Company or
one of its Participating Subsidiaries. It shall not include any person who is
recorded on the books and records of the Company or one of its Participating
Subsidiaries as an independent contractor or consultant or a worker provided by
a temporary staffing agency.

         (j) "Enrollment Date" means the first day of each Offering Period.

         (k) "Exercise Date" means each July 31 and January 31 during each
Offering Period.

         (l) "Exercise Period" means a period commencing on February 1 and
terminating on the following July 31 or commencing on August 1 and terminating
on the following January 31.

         (m) "Exercise Price" means the price per share of shares offered in a
given Offering Period determined as provided in Section 10 below.

         (n) "Fair Market Value" means, with respect to a share of Common Stock
as of any Enrollment Date or Exercise Date, the closing price of such Common
Stock on the New York Stock Exchange on such date, as reported in The Wall
Street Journal. In the event that such a closing price is not available for an
Enrollment Date or an Exercise Date, the Fair Market Value of a share of Common
Stock on such date shall be the closing price of a share of the Common Stock on
the New York Stock Exchange on the last business day prior to such date or such
other amount as may be determined by the Committee by any fair and reasonable
means.

         (o) "Offering Period" means a period of twenty-four (24) months during
which an option granted pursuant to the Plan may be exercised. A new Offering
Period shall begin on each February 1 and August 1.

         (p) "Participant" means an Eligible Employee who has elected to
participate in the Plan by filing an enrollment agreement with the Company as
provided in Section 7 below.

         (q) "Participating Subsidiary" means any Subsidiary other than a
Subsidiary excluded from participation in the Plan by the Committee, in its sole
discretion.

         (r) "Plan" means this Western Digital Corporation 1993 Employee Stock
Purchase Plan.

         (s) "Subsidiary" means any corporation, domestic or foreign, of which
the Company owns, directly or indirectly, not less than 50% of the total
combined voting power of all classes of stock or other equity interests and that
otherwise qualifies as a "subsidiary corporation" within the meaning of Section
424(f) of the Code or any successor thereto.

         2. Purpose of the Plan.

         The purpose of the Plan is to provide an incentive for present and
future Employees of the Company and its Participating Subsidiaries to acquire a
proprietary interest (or increase an existing proprietary interest) in the
Company through the purchase of Common Stock. It is the intention of the Company
that the Plan qualify as an "employee stock purchase plan" under Section 423 of
the Internal Revenue Code of 1986. Accordingly, the provisions of the Plan shall
be administered, interpreted and construed in a manner consistent with the
requirements of that section of the Code.

         3. Shares Reserved for the Plan.

         There shall be reserved for issuance and purchase by Participants under
the Plan an aggregate of 11,000,000 shares of Common Stock, subject to
adjustment as provided in Section 15 below. Shares of Common Stock subject to
the Plan may be newly issued shares or shares reacquired in private transactions
or open market purchases. If and to the extent that any right to purchase
reserved shares shall not be exercised by any Participant for any reason or if
such right to purchase shall terminate as provided herein, shares that have not
been so purchased hereunder shall again become available for the purposes of the
Plan unless the Plan shall have been terminated, but all shares sold under the
Plan, regardless of source, shall be counted against the limitation set forth
above.

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          4. Administration of the Plan.

         (a) The Plan shall be administered by a Committee appointed by, and
which shall serve at the pleasure of, the Board. The Committee shall consist of
not less than 3 members of the Board who are not officers or employees of the
Company or of any of its Subsidiaries and who are disinterested persons within
the terms of Rule 16b-3 promulgated under the Securities Exchange Act of 1934.
The Committee shall have authority to interpret the Plan, to prescribe, amend
and rescind rules and regulations relating to the Plan, and to make all other
determinations necessary or advisable for the administration of the Plan, all of
which actions and determinations shall be final, conclusive and binding on all
persons.

         (b) The Committee may request advice or assistance or employ such other
persons as it in its absolute discretion deems necessary or appropriate for the
proper administration of the Plan, including, but not limited to employing a
brokerage firm, bank or other financial institution to assist in the purchase of
shares, delivery of reports or other administrative aspects of the Plan.

         5. Eligibility to Participate in the Plan.

         Subject to limitations imposed by Section 423(b) of the Code, any
Employee who is employed by the Company or a Participating Subsidiary on an
Enrollment Date shall be eligible to participate in the Plan for the Offering
Period beginning on that Enrollment Date.

         6. Offering Periods.

         The Plan shall be implemented by consecutive Offering Periods with a
new Offering Period commencing on each February 1 and August 1 during the term
of the Plan. The first such Offering Period shall commence on February 1, 1994,
or as otherwise determined by the Committee. The Committee shall have the power
to change the duration of Offering Periods with respect to future offerings
without shareholder approval if such change is announced at least fifteen (15)
days prior to the scheduled beginning of the first Offering Period to be
affected.

         7. Election to Participate in the Plan.

         (a) Each Eligible Employee may elect to participate in the Plan by
completing an enrollment agreement in the form provided by the Company and
filing such enrollment agreement with the Company prior to the applicable
Enrollment Date, unless another time for filing the enrollment form is set by
the Committee for all Eligible Employees with respect to a given Offering
Period. An Eligible Employee may participate in an Offering Period only if, as
of the Enrollment Date of such Offering Period, such Eligible Employee is not
participating in any prior Offering Period which is continuing at the time of
such proposed enrollment.

         (b) Payroll deductions for a Participant shall commence on the first
payroll date following the Enrollment Date and shall end on the last payroll
date in the Offering Period to which such authorization is applicable, unless
sooner terminated by the Participant as provided in Section 12.

         (c) Unless a Participant elects otherwise prior to the Enrollment Date
of the immediately succeeding Offering Period, an Eligible Employee who is
participating in an Offering Period as of the last Exercise Date of such
Offering Period (the "Prior Offering Period") shall be deemed (i) to have
elected to participate in the immediately succeeding Offering Period and (ii) to
have authorized the same payroll deduction for such immediately succeeding
Offering Period as was in effect for such Participant immediately prior to the
expiration or termination of the Prior Offering Period.

         (d) The Committee, in its discretion, may terminate the participation
of all Participants in any Offering Period as of the last day of any Exercise
Period (a "Termination Date") and enroll such Participants in the new Offering
Period commencing immediately following such Termination Date if the Exercise
Price determined as of the Enrollment Date for such new Offering Period is lower
than the Exercise Price determined as of the Enrollment Date of the Offering
Period for which the Participants' participation is being terminated. In such
event, each of such Participants shall be deemed for purposes of this Plan (i)
to have elected to participate in such new Offering Period and

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(ii) to have authorized the same payroll deduction for such new Offering Period
as was in effect for such Participant immediately prior to the Termination Date.

         8. Payroll Deductions.

         (a) All Participant contributions to the Plan shall be made only by
payroll deductions. At the time a Participant files the enrollment agreement
with respect to an Offering Period, the Participant shall authorize payroll
deductions to be made on each payroll date during the Offering Period in an
amount of from 1% to 10% of the Eligible Compensation which the Participant
receives on each payroll date during such Offering Period. The amount of such
payroll deductions shall be a whole percentage (i.e., 1%, 2%, 3%, etc.) of the
Participant's Eligible Compensation.

         (b) All payroll deductions made for a Participant shall be deposited in
the Company's general corporate account and shall be credited to the
Participant's account under the Plan. No interest shall accrue or be credited
with respect to the payroll deductions of a Participant under the Plan. A
Participant may not make any additional payments into such account. All payroll
deductions received or held by the Company under the Plan may be used by the
Company for any corporate purpose, and the Company shall not be obligated to
segregate such payroll deductions.

         (c) A Participant may discontinue participation in the Plan as provided
in Section 12. A Participant may at any time during an Offering Period (but no
more than four times in any calendar year) reduce or increase (subject to the
limitations of Section 8(a) above) the rate of his or her payroll deductions by
completing and filing with the Company a change notice in the form provided by
the Company. Any such reduction in the rate of a Participant's payroll
deductions shall be effective as of the pay period specified by the Participant
in the Participant's change notice, but in no event sooner than the first pay
period ending more than fifteen (15) days after the Participant files the change
notice with the Company. Any such increase in the rate of a Participant's
payroll deductions shall be effective as of the first date of the next Exercise
Period within such Offering Period.

         9. Grant of Options.

         (a) On the Enrollment Date of each Offering Period, subject to the
limitations set forth in Sections 3 and 9(b) hereof, each Participant shall be
granted an option to purchase on each Exercise Date during such Offering Period
(at the Exercise Price determined as provided in Section 10 below) up to a
number of shares of the Company's Common Stock determined by dividing such
Participant's payroll deductions accumulated during the Exercise Period ending
on such Exercise Date by 85% of the fair market value of a share of the
Company's Common Stock on the Enrollment Date or on the Exercise Date, whichever
is lower, provided that the number of shares subject to the option shall not
exceed five (5) times the number of shares determined by dividing 10% of the
Participant's Eligible Compensation over the Offering Period (determined based
upon the Eligible Employee's rate of Eligible Compensation in effect as of the
Enrollment Date) by 85% of the Fair Market Value of a share of the Company's
Common Stock on the Enrollment Date.

         (b) Notwithstanding any provision of the Plan to the contrary, no
Participant shall be granted an option under the Plan (i) if, immediately after
the grant, such Participant (or any other person whose stock would be attributed
to such Participant pursuant to Section 424(d) of the Code) would own stock
and/or hold outstanding options to purchase stock possessing 5% or more of the
total combined voting power or value of all classes of stock of the Company or
of any Subsidiary of the Company, or (ii) which permits such Participant's
rights to purchase stock under all employee stock purchase plans of the Company
and its Subsidiaries to accrue at a rate which exceeds $25,000 of fair market
value of such stock (determined at the time such option is granted) for each
calendar year in which such option is outstanding at any time.

         10. Exercise Price.

         The Exercise Price of each of the shares offered in a given Offering
Period shall be the lower of: (i) 85% of the Fair Market Value of a share of the
Common Stock of the Company on the Enrollment Date; or (ii) 85% of the Fair
Market Value of a share of the Common Stock of the Company on the applicable
Exercise Date.

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         11. Exercise of Options.

         Unless a Participant withdraws from the Plan as provided in Section 12,
the Participant's option for the purchase of shares will be exercised
automatically on each Exercise Date of the Offering Period, and the maximum
number of full shares subject to option will be purchased for the Participant at
the applicable Exercise Price with the accumulated payroll deductions in the
Participant's account. Any amount remaining in the Participant's account after
an Exercise Date shall be held in the account until the next Exercise Date in
such Offering Period, unless the Offering Period has been over-subscribed or has
terminated with such Exercise Date, in which event such amount shall be refunded
to the Participant.

         12. Withdrawal; Termination of Employment.

         (a) A Participant may withdraw all but not less than all of the payroll
deductions credited to the Participant's account under the Plan at any time by
giving written notice to the Company. All of the Participant's payroll
deductions credited to the Participant's account will be paid to him promptly
after receipt of the Participant's notice of withdrawal, the Participant's
participation in the Plan will be automatically terminated, and no further
payroll deductions for the purchase of shares will be made. Payroll deductions
will not resume on behalf of a Participant who has withdrawn from the Plan
unless written notice is delivered to the Company within the open enrollment
period preceding the commencement of an Exercise Period directing the Company to
resume payroll deductions.

         (b) Upon termination of the Participant's Continuous Employment prior
to the Exercise Date of an Offering Period for any reason, including retirement
or death, the payroll deductions credited to the Participant's account will be
returned to the Participant or, in the case of death, to the Participant's
estate, and the Participant's options to purchase shares under the Plan will be
automatically terminated.

         (c) In the event a Participant fails to maintain Continuous Employment
for at least twenty (20) hours per week during an Offering Period, the
Participant will be deemed to have elected to withdraw from the Plan, the
payroll deductions credited to the Participant's account will be returned to the
Participant, and the Participant's options to purchase shares under the Plan
will be terminated.

         (d) A Participant's withdrawal from an Offering Period will not have
any effect upon the Participant's eligibility to participate in a succeeding
Offering Period or in any similar plan which may hereafter be adopted by the
Company.

         13. Transferability.

         Options to purchase Common Stock granted under the Plan are not
transferable by a Participant other than by will or the laws of descent and
distribution and are exercisable during a Participant's lifetime only by the
Participant.

         14. Reports.

         Individual accounts will be maintained for each Participant in the
Plan. Statements of account will be given to Participants semi-annually promptly
following each Exercise Date, which statements will set forth the amounts of
payroll deductions, the per share purchase price, the number of shares purchased
and the remaining cash balance, if any.

         15. Adjustments Upon Changes in Capitalization.

         (a) If the outstanding shares of Common Stock are increased or
decreased, or are changed into or are exchanged for a different number or kind
of shares, as a result of one or more reorganizations, restructurings,
recapitalizations, reclassifications, stock splits, reverse stock splits, stock
dividends or the like, appropriate adjustment shall be made in the number and/or
kind of shares, and the per-share option price thereof, which may be issued in
the aggregate and to any Participant upon exercise of options granted under the
Plan.

         (b) In the event of the proposed dissolution or liquidation of the
Company, each Offering Period will terminate immediately prior to the
consummation of such proposed action, unless otherwise provided by the

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Committee. In the event of a proposed sale of all or substantially all of the
assets of the Company, or the merger of the Company with or into another
corporation, each option under the Plan shall be assumed or an equivalent option
shall be substituted by such successor corporation or a parent or subsidiary of
such successor corporation, unless the Committee determines, in the exercise of
its sole discretion and in lieu of such assumption or substitution, that the
Participant shall have the right to exercise the option as to all of the
optioned stock, including shares as to which the option would not otherwise be
exercisable. If the Committee makes an option fully exercisable in lieu of
assumption or substitution in the event of a merger or sale of assets, the
Committee shall notify the Participant that the option shall be fully
exercisable for a period of thirty (30) days from the date of such notice, and
the option will terminate upon the expiration of such period.

         (c) In all cases, the Committee shall have full discretion to exercise
any of the powers and authority provided under this Section 15, and the
Committee's actions hereunder shall be final and binding on all Participants. No
fractional shares of stock shall be issued under the Plan pursuant to any
adjustment authorized under the provisions of this Section 15.

         16. Amendment of the Plan.

         The Board may at any time, or from time to time, amend the Plan in any
respect; provided, however, that the Plan may not be amended in any way that
will cause rights issued under the Plan to fail to meet the requirements for
employee stock purchase plans as defined in Section 423 of the Code or any
successor thereto, including, without limitation, shareholder approval if
required.

         17. Termination of the Plan.

         The Plan and all rights of Employees hereunder shall terminate:

         (a) on the Exercise Date that Participants become entitled to purchase
a number of shares greater than the number of reserved shares remaining
available for purchase under the Plan; or

         (b) at any time, at the discretion of the Board.

         In the event that the Plan terminates under circumstances described in
Section 17(a) above, reserved shares remaining as of the termination date shall
be sold to Participants on a pro rata basis.

         18. Notices.

         All notices or other communications by a Participant to the Company
under or in connection with the Plan shall be deemed to have been duly given
when received in the form specified by the Company at the location, or by the
person, designated by the Company for the receipt thereof.

         19. Shareholder Approval.

         Continuance of the Plan shall be subject to approval by the
shareholders of the Company within twelve months before or after the date the
Plan is adopted. If such shareholder approval is obtained at a duly held
shareholders' meeting, it may be obtained by the affirmative vote of the holders
of a majority of the outstanding shares of the Company present or represented
and entitled to vote thereon.

         20. Conditions Upon Issuance of Shares.

         (a) The Plan, the grant and exercise of options to purchase shares of
Common Stock under the Plan, and the Company's obligation to sell and deliver
shares upon the exercise of options to purchase shares shall be subject to all
applicable federal, state and foreign laws, rules and regulations, and to such
approvals by any regulatory or governmental agency as may, in the opinion of
counsel for the Company, be required.

         (b) The Company may make such provisions as it deems appropriate for
withholding by the Company pursuant to federal or state income tax laws of such
amounts as the Company determines it is required to withhold in

                                       6
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connection with the purchase or sale by a Participant of any Common Stock
acquired pursuant to the Plan. The Company may require a Participant to satisfy
any relevant tax requirements before authorizing any issuance of Common Stock to
such Participant.

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