Retention Agreement - Storage Technology Corp. and Robert S. Kocol

July 31, 2000

Mr. Robert S. Kocol
577 Manorwood Lane
Louisville, Colorado 80027

                  RE: Extension to Retention Agreement

Dear Bobby:

Your  Retention  Agreement  dated January 27, 2000 (the  "Retention  Agreement")
provides  that you will  remain an employee  of Storage  Technology  Corporation
("StorageTek") through at least July 31, 2000 (the "Termination Date" as defined
in the  Retention  Agreement).  This letter will confirm our agreement to extend
the Termination  Date of your employment with StorageTek until at least December
31, 2000 (the "New  Termination  Date")  pursuant to the terms of the  Retention
Agreement (said extension interval to be called the "Extension Period").  Unless
specifically  modified in this  letter,  all other terms and  conditions  in the
Retention Agreement will remain in effect.

As further consideration for the expansion of your current  responsibilities and
the extension of your employment with the StorageTek through the New Termination
Date,  StorageTek  will pay you (i) an additional  cash payment in the amount of
$50,000.00  within  fifteen  working  days  of the  date  hereof,  and  (ii)  an
additional  payment  in the  amount  of  $50,000.00,  within  30 days of the New
Termination  Date.  This additional  consideration  is subject to same terms and
conditions as outlined in the "Separation  Payment"  paragraph of your Retention
Agreement, and will be paid to you in addition to the amounts stated therein.

You  further  agree  and  acknowledge  that you will  have 90 days  from the New
Termination  Date to exercise  any of your stock  options that are vested on the
New Termination Date.  However,  should your  responsibilities as an employee of
the StorageTek during the Extension Period render you ineligible to trade in the
StorageTek's  stock due to your possession of "material  inside  information" on
the New  Termination  Date,  you and the  StorageTek  may agree to enter  into a
consulting  agreement  for a period of time not to exceed 90 days,  during which
time all stock options (i) which were granted to you under the  StorageTek  1995
Equity  Participation Plan, and (ii) which were vested and exercisable by you on
the New  Termination  Date will  remain  exercisable  by you for the term of the
consulting period and for a period of 90 days thereafter.

All terms of your Retention Agreement remain in full force with the exception of
the above revisions.

Please sign both copies of this letter below,  indicating your  acceptance,  and
return one copy for our files.

Accepted and Agreed:                            StorageTek:

/s/ Robert S. Kocol                     /s/ Patrick J. Martin
-----------------                         ---------------------
Robert S. Kocol                                 Patrick J. Martin
                                                Chairman, President and
Chief Executive Officer