Int 25  - Dos 3.31+ - Absolute Disk Read (32m-2047m Hard-disk Partition)   [D]

   CX = FFFFh
   AL = drive number (0=A, 1=B, etc)
   DS:BX -> disk read packet (see #2236)

Return: CF clear if successful
   CF set on error
       AH = status (see #2235)
       AL = error code (same as passed to INT 24 in DI)
   may destroy all other registers except segment registers

Notes: partition is potentially >32M (and requires this form of the call) if
     bit 1 of the device attribute word in the device driver is set
   original flags are left on stack, and must be removed by caller
   this call bypasses the DOS filesystem
   for FAT32 drives (which may be up to 2TB in size), use INT 21/AX=7305h

See Also: INT 13/AH=02h,INT 25,INT 26/CX=FFFFh,INT 21/AX=7305h

Format of disk read packet:
Offset Size    Description (Table 2236)
 00h   DWORD   sector number
 04h   WORD    number of sectors to read
 06h   DWORD   transfer address

See Also: #2240