Int 21 Fn 4404  - Stacker - Get Stacvol File Sectors                       [k]

   AX = 4404h
   BL = drive number (0 is current drive)
   CX = byte count (i.e., 200h = 1 sector)
   DS:DX -> buffer (see #1216)

Return: Data Buffer contains the number of sectors requested from the
     STACVOL physical file for the drive specified.

Format of Stacker buffer:
Offset Size    Description (Table 1216)
 00h   WORD    01CDh
 02h   WORD    sector count
 04h   DWORD   number of starting sector
 08h   DWORD   far pointer to Data Buffer