Category: <b>other operating systems</b>
<p>
<pre><b>INT 2F - DR DOS 6.0+ IBMBIO.COM - REGISTER ROOT OF UPPER MEMORY LINK</b>

	AX = 12FFh
	BX = 0009h
	DX = new value for root segment of upper memory link
Return: AX = 0000h if supported
	ES:BX modified
Notes:	the DX value is stored at offset 66h in SYSVARS (see INT 21h/AH=52h)
	  and offset 18h in the Novell DOS 7 internal variable table
	  (see INT 21/AX=4458h)
	This API is provided by IBMBIO.COM for the initialization phase
	  of drivers loaded via DEVICE=/HIDEVICE=/DEVICEHIGH= directives and
	  is only available during these short time intervals.  It is probably
	  initiated by the Novell DOS 7+ EMM386.EXE.
	this function has apparently been supported since DR DOS 6.0 "Buxton"
	  of 1991/03/19
	for Novell DOS 7, ES:BX points at the internal variable table DRDAT,
	  but this may change in future releases
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