My friends father still uses his commodore 64.  He was looking for
information or a manual for a hard drive that he uses for the
commodore.  All the info I have is it is a STC-100.

Marc, with only so little to go on, finding you hard drive seems to be
a vast difficult task. There's alot of html pages on old c64 hardware,
but I'v never heard of a STC-100 for the commodore 64. Must hard
drives back them was
made my commodore themselfes.

- Do you have the possibility to get a frontside/backside photo of it ?. 
- Are you abosolutly sure it called STC-100 ?. 
- Since it's a hard drive, do you known the size in megabytes of it ?.
- Most electronic equipment was a label ... 'made in' and so on...
what does it say ?

/Jacob

STC-100 is a Seagate Technologies Corporation 10MB Hard drive.  

What else you need to know?  Interface type was probably the precursor
to IDE if I remember it correctly.

I remember seeing one of these being attached to a Commodore Amiga
system.  I was amazed at the wonderous device that didn't need a
floppy for storage any more :)