EXHIBIT 10.21

                             FIRST ADDENDUM TO LEASE



This First  Addendum to Lease is made and  entered  into the 22nd day of August,
1995,  between Conifer Prince Street Associates  (Landlord) and DSMI Corporation
(Tenant).

WITNESSETH: that Tenant currently leases and occupies approximately 3,573 square
feet of office space at 46 Prince Street,  Rochester, New York 14607 pursuant to
a Lease Agreement dated February 22, 1995 (Lease).  WHEREAS, Tenant and Landlord
desire to expand Tenant's Leased Premises as illustrated on Exhibit A-1 attached
hereto, and made a part of the First Addendum to Lease.

NOW,  THEREFORE,  it is mutually  agreed  upon by Landlord  and Tenant to modify
certain provisions of the Lease as follows:

     1. Effective upon full execution of this First Addendum to Lease,  Tenant's
leased premises shall be approximately 5,504 rentable square feet.

     2. Effective  upon full execution of this First Addendum to Lease,  Section
1, "TERM",  Paragraph A, of the Lease Agreement  shall be modified,  in part, to
read "... and  terminating on September 30,  1999..."  Additionally,  Tenant has
hereby exercised a modification of the extension period as stated within Section
1, Paragraph B, of the Lease Agreement.  Therefore, the provisions of Section 1.
"TERM", Paragraph B, of the Lease Agreement shall now be null and void.

     3. Effective  upon full execution of this First Addendum to Lease,  Section
2, "RENTAL",  of the Lease Agreement shall be modified, in part, as follows "...
the Base Rent shall be increased as follows:
             Period                 $/Sq.ft.           Monthly        Annual  
                                                      Base Rent      Base Rent 
         10/1/95-2/28/96            $12.50           $ 5,136.46*        N/A
         3/1/96-2/28/97             $13.00           $ 5,962.67     $ 71,552.00
         3/1/97-2/28/98             $13.50           $ 6,192.00     $ 74,304.00
         3/1/98-2/28/99             $14.00           $ 6,421.33     $ 77,055.96
         3/1/99-9/30/99             $14.50           $ 6,650.67         N/A

     * Landlord  agrees to abate the Base Rent for 573 square  feet of the newly
created demised  premises during the period of October 1, 1995 through  February
28, 1996. Therefore, Base Rent is based on 4,931 square feet during such period.

     4. Effective  upon full execution of this First Addendum to Lease,  Section
5,  "Services",  of the Lease  Agreement shall be modified to include Exhibit AA
"Landlord/Tenant  Work Letter"  attached to and made part of this First Addendum
to Lease.

     5. Effective  upon full execution of this First Addendum to Lease,  Section
33, "First Right To Lease",  of the Lease Agreement shall be modified,  in part,
to read"...space within the building..." and the words "said approximately 3,741
square feet or any portion  thereof on the first floor" shall be replaced by the
following, "space within the Building"

     6. Effective upon full execution of this First Addendum to Lease,  Schedule
A, of the Lease Agreement shall be replaced by Schedule A-2, attached and made a
part of this First Addendum to Lease.

     7. Effective upon full execution of this First Addendum to Lease,  Schedule
B "Services Provided by Landlord" of the Lease Agreement,  shall be modified, in
part, to read "...Item 6, Parking for 17 effective October 1, 1995 and increased
to 25 effective February 1, 1996".

     8.  Tenant  shall  have a  one-time  opportunity  to  terminate  the  Lease
Agreement  effective  September  30, 1998.  Tenant must provide  Landlord with a
minimum of 120 days written notice of its intention to exercise its  termination
option.  Furthermore, in order for Tenant's option to be effective, it's written
notice must be delivered to Landlord together with an early termination  penalty
equal to $10,500.00.

     9. Prior to Tenant's  occupancy  of the  expansion  space,  Landlord  shall
relocate the ground wire connection servicing Tenant's electrical panel from its
current  position,  so that it connects  directly  into a ground pole within the
panel.

     Except as  modified  above,  all other  terms and  conditions  of the Lease
Agreement  dated February 22, 1995 shall remain  unchanged and in full force and
effect.


Agreed to by:                                        Agreed to by:

DSMI CORPORATION  CONIFER PRINCE STREET ASSOCIATES



By:  /s/ Gregory D. Brown                        By:  /s/ C. Terrance Butwid    


Date:  August 18, 1995                           Date:   August 22, 1995      
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