Re: increase base memory

[John Elliott <jce@seasip.demon.co.uk>]

: Ralf Brown memory.lst states:
: --------V-MA0000000--------------------------
: MEM A000h:0000h - EGA+ GRAPHICS BUFFER
: Size:	65536 BYTEs
: 
: So it was always there.

  Well, at least since the EGA. I suppose if DOSEMU emulated an MDA or a
CGA, then it would make sense to use the memory up to B000:0 or B800:0
respectively. On an original XT, it was even possible to do this in
hardware:
<ftp://ftp.simtel.net/pub/simtelnet/msdos/info/896k-mem.txt>
 
: QEMM have a program called "vidram", which allows to use that region as a
: base memory by the cost of not being able to diplay graphics, but vidram
: will not work under dosemu because qemm itself doesn't work under dosemu.

  The same thing is true of DRDOS (the equivalent program is called MEMMAX).

--------m-2F12FFBX0006-----------------------
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)

: Increasing the base memory above 640Kb is definitely the bad idea, as it
: is used very rarely even in a pure DOS and will cost you the inability to
: display graphics.

  Except in the CGA modes :-)

-- 
John Elliott