DOS Absolute disk write (INT 26h)

        Normal DOS (DOS 2.x and 3.x):
          Entry:
            AL    = Drive number (0=A, 1=B, etc)
            DS:BX = Disk Transfer Address (buffer)
            CX    = Number of sectors to write
            DX    = First relative sector to write
          Return:
            CF = 1 if error
            AL = error code issued to INT 24h in low half of DI
            AH = same error codes as for INT 25h

          Note: ORIGINAL FLAGS ON STACK!


        PC DOS 4.0

          Entry:
            AL    =  Drive number (0=A, 1=B, etc)
            DS:BX =  Pointer to request package
            CX    =  Number of sectors to write
            DX    =  First relative sector to write
          Return:
            CF    = 1 if error
            AL    = error code issued to INT 24h in low half of DI
            AH    = 80h if attachment failed to respond
                    40h if seek operation failed
                    20h if controller failed
                    10h if data error (bad CRC)
                    08h if DMA failure
                    04h if requested sector not found
                    03h if write-protected disk
                    02h if bad address mark
                    01h if bad command

        Request package:
        Name    Size    ; Contens                                     
        RBA     DD      ; First sector to write (0=first on disk)
        Count   DW      ; Number of sectors to write
        Buffer  DD      ; Pointer to databuffer, where data is placed.



        COMPAQ DOS 3.31 - >32M hard-disk partition
          Entry:
            AL    = Drive number (0=A, 1=B, etc)
            CX    = FFFFh
            DS:BX = Packet address
                      DWORD sector number
                      WORD  number of sectors to write
                      DWORD transfer address
          Return:
             Same as above???

          Note: Partition is potentially >32M (and requires this form of
          the call) if bit 1 of device attribute word in device driver
          is set.