Int 4D Fn 08  - Ti Professional Pc - Disk - Set Standard Device Interface  [B]

   AH = 08h
   DL = drive number (00h-03h)
   AL = drive type
       00h single-sided 48 tpi (40-track, 8 sectors, 512 bytes/sector)
       01h double-sided 48 tpi (40-track, 8 sectors, 512 bytes/sector)
       02h single-sided 96 tpi (80-track, 8 sectors, 512 bytes/sector)
       03h double-sided 96 tpi (80-track, 8 sectors, 512 bytes/sector)

Return: nothing???

See Also: AH=00h,AH=09h