Int 26  - Dos 1+ - Absolute Disk Write (except Partitions > 32m)           [D]

   AL = drive number (00h = A:, 01h = B:, etc)
   CX = number of sectors to write (not FFFFh)
   DX = starting logical sector number (0000h - highest sector on drive)
   DS:BX -> data to write

Return: CF clear if successful
   CF set on error
       AH = status (see #2235)
       AL = error code (same as passed to INT 24 in DI)
       AX = 0207h if more than 64K sectors on drive -- use new-style call
   may destroy all other registers except segment registers

Notes: original flags are left on stack, and must be popped by caller
   this call bypasses the DOS filesystem, though DOS 5+ invalidates any
     disk buffers referencing sectors which are written with this call
   examination of CPWIN386.CPL indicates that if this call fails with
     error 0408h on an old-style (<32M) call, one should retry the
     call with the high bit of the drive number in AL set
   Novell DOS 7 decides whether the old-style or new-style (>32M) version
     of INT 26 must be used solely on the basis of the partition's size,
     thus forcing use of the new-style call even for data in the first
     32M of the partition
BUGS:  DOS 3.1 through 3.3 set the word at ES:[BP+1Eh] to FFFFh if AL is an
     invalid drive number
   DR DOS 3.41 will return with a jump instead of RETF, leaving the
     wrong number of bytes on the stack; use the huge-partition version
     (INT 26/CX=FFFFh) for all partition sizes under DR DOS 3.41

See Also: INT 13/AH=03h,INT 25,INT 26/CX=FFFFh,INT 21/AX=7305h