Int 13 Fn 20  u - Quickcache Ii V4.20 - Dismount                           [c]

   AH = 20h
   AL = drive (00h = A:, etc. or 7Fh for all removable drives???
                  or FFh for all drives)

Return: AX = status (0000h successful)
Program: QUICKCACHE II is a shareware disk cache by P.R. Glassel and
     Associates, Inc.
Desc:  flush any dirty buffers for the specified drive(s) and then discard
     those sector buffers

See Also: AH=21h,AH=22h,AH=28h