INT 2F - Ergo DOS extenders - INSTALLATION CHECK

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