Int 2F Fn D44D  - 4dos.com V2.1+ - API                                     [l]

   AX = D44Dh
   BH = function
       00h installation check

       Return: AX = 44DDh
           BL = major version number
           BH = minor version number
           CX = PSP segment address for current invocation
           DL = 4DOS shell number (0 for the first (root) shell,
                updated each time a new copy is loaded)
       01h (internal, v2.1-3.03) terminate current copy of 4DOS

       Return: nothing
       (internal, v4.0) ???

       Return: AX = 44DDh
           ES:BX -> data area (see below)
       02h ???
       DX = ???
   ---v2.1-3.03 only---
       03h EXEC program
       CX:DX -> EXEC record
       FEh deallocate shell number (passed through to root shell)
       ???
       FFh allocate shell number (passed through to root shell)

Note:  bug in v3.00 will crash system if unrecognized value in BH

See Also: AX=D44Eh,AX=E44Dh,INT 21/AX=4403h
Index: installation check;4DOS|installation check;NDOS

Format of EXEC record:
Offset Size    Description
 00h   WORD    offset of ASCIZ program name in same segment as EXEC record
 02h   WORD    offset of DOS commandline in same segment as EXEC record
 04h   WORD    segment of environment for child process (see INT 21/AH=26h)

Format of 4DOS v4.0 data area:
Offset Size    Description
 00h  2 BYTEs  ???
 06h   WORD    XMS handle for swapping
   ???