Category: <b>vendor-specific BIOS extensions</b>
<p>
<pre><b>INT 15 - Compaq ROM BIOS 1993/08/03 and newer - ???</b>

	AH = E4h
	AL = subfunction
	    00h get advanced system info
		Return: CF clear
			AH = 00h
			CX = 0000h
			BX = advanced system info flags (read from [XBDA:0094h])
			     bit 4: "mode 2" (dual harddisk controller) enabled
	    01h,02h unsupported by this ROM version
		Return: CF set, AH = 86h
	    80h set advanced system info
		BX = advanced system info flags
		     bit 4: enable "mode 2" (dual harddisk controller)
		???
		Return: ???
		Note:	On Compaq machines with "COMPAQ" signature at
			  F000h:FFEAh (see also MEM F000h:FFE0h), MS-DOS/PC DOS
			  IO.SYS/IBMBIO.COM use	this function to set bit 4
			  before calling INT 13h/AH=08h to retrieve the number
			  of hard disks installed (DL).
	    90h,A0h,B0h,C0h,D0h,E0h,F0h set ???
		Return: CF clear
			AH = 00h
			CX = 0000h
			BX = ???
	    81h,91h,A1h,B1h,C1h,D1h,E1h,F1h unsupported by 3/8/93&amp4/8/93 ROMs
		Return: CF set, AH = 86h
Notes:	functions 80h/90h/etc. are not supported by the 4/8/93 EISA System ROM
	these functions are not supported by the 7/26/93 LTE Lite 386 ROM
</pre>