Int 13 Fn 39  U - Quickcache Ii V4.20 - Set Read Buffer Size For Specific  [c]

   AH = 39h
   AL = new size of read buffer
   DL = drive number (00h = A:)

Return: AX = status (0000h successful)
Program: QUICKCACHE II is a shareware disk cache by P.R. Glassel and
     Associates, Inc.

See Also: AH=2Ah,AH=3Ah