Int 2F Fn A1  - Ergo DOS Extenders - Installation Check                    [E]

   AH = A1h
   BX = 0081h
   AL = which
       FEh OS/286,OS/386
       FFh HummingBoard DOS extender
   ES:DI -> 16-byte buffer

Return: if installed, first four bytes of ES:DI buffer are "IABH"

Note:  since TKERNEL is a licensed version, it is likely that subfunctions
     BX=0082h and BX=0084h are present and function identically to the
     AX=FBA1h/BX=008xh calls

See Also: AX=ED00h,AX=FBA1h/BX=0081h,INT 15/AX=BF02h