INT 2F U - DR DOS 6+, Novell DOS 7+ - EMM386.EXE - VIDEO MEMORY SPACE CONTROL   
	AX = 12FFh
	BX = 0006h
	DX = 0000h
	CX = function
	    0000h get status of video memory space (MEMMAX /V)
	    0001h map memory into video memory space (MEMMAX +V)
	    0002h unmap memory from video memory space (MEMMAX -V)
Return: CF clear if successful
	    AX = 0000h (successful)
	    BX = segment of reserved video RAM(Random Access Memory)	See also DRAM, SRAM.
	    CX = segment of used video RAM(Random Access Memory)	See also DRAM, SRAM.
	    DX = segment of first upper MCBsee Memory Control Block
Notes:	this functionality is provided by EMM386, and partially supported by
	  HIDOS.SYS
	BL specifies which program handles the call, BH is the function number
BUG:	4DOS 5.51(a) often hangs the system (reported to be reproducable), if
	  MEMMAX +V is issued from the 4DOS prompt.  To avoid this, one should
	  temporary load COMMAND.COM followed by MEMMAX +v , starting the
	  application, MEMMAX -v and EXIT.  4DOS 5.5c does not show this
	  phenomena on the same systems where 5.51a hangs.
SeeAlso: AX=D201h/BX=4849h


(Table 04105)
Values for DR DOS memory space control error code:
 00h	successful
 80h	video memory already unmapped
 81h	video memory already mapped
 82h	no video memory reserved (/VIDEO not specified)
 83h	video memory in use (graphics mode or non-standard text mode)
 84h	mapped video memory contains allocated arena(s)
 85h	hardware error
 86h	driver requires protected mode but is permanently in real mode
	  ("EMM386 OFF")