Int 21 Fn 1A  - Dos 1+ - Set Disk Transfer Area Address                    [D]

   AH = 1Ah
   DS:DX -> Disk Transfer Area (DTA)

Notes: the DTA is set to PSP:0080h when a program is started
   under the FlashTek X-32 DOS extender, the pointer is in DS:EDX

See Also: AH=11h,AH=12h,AH=2Fh,AH=4Eh,AH=4Fh