Dec 072017
 
Some tips that may help you recover more DOS usable memory when using Quaterdeck's QEMM 386 memory manager.
File QEMM.ZIP from The Programmer’s Corner in
Category Tutorials + Patches
Some tips that may help you recover more DOS usable memory when using Quaterdeck’s QEMM 386 memory manager.
File Name File Size Zip Size Zip Type
QEMM.TXT 2048 1025 deflated

Download File QEMM.ZIP Here

Contents of the QEMM.TXT file


Recently I discovered a little know fact about QEMM. With a little searching
you can remap RAM into a unused ROM location. On my Everex Step 386/20, this
results in a gain of 24K. This was very helpful to me due to the fact that I
must exclude Ram for both a video card and a network card.

There may be some of you hackers out there who would like to write a program
to locate all unused ROM locations in a computer. I would recommend to just
upgrade to QEMM 5.0 when it arrives. I have been told by Quarterdeck Tech, that
5.0 has a program to evaluate all memory locations and to use them as mappable
memory.

For now just use DOS DEBUG. All typed commands will be entered in [ ]'s. Don't
type the [ ]'s just the commands. [ENTER] is used for the return or enter key.

[DEBUG][ENTER]

-[RCS][ENTER]

CS xxxx

:[F000][ENTER]

-[DCS:0000 0FFF][ENTER] ;Numbers will scroll by, watch for numbers
;other than 00's. If any occur you can't
;remap this section.
-[DCS:1000 1FFF][ENTER] ;This section in my 386 was blank. There
;must be no code in an area to use it for
;High RAM.
-[DCS:2000 2FFF][ENTER] ;Continue this for [DCS:3000 3FFF] Through
;[DCS:F000 FFFF] taking note of any blanks.
-[DCS:XXXX XXXX][ENTER] ;Remember A000 follows 9FFF and so on.

-[Q][ENTER] ;This will return you to a DOS prompt.

Each section is 4K of memory. QEMM doesn't like breaking it down any further
than 4K. So if there is ANY code in a section don't try to use it!

Next you will need to edit your CONFIG.SYS file. Mine turned out like this:


DEVICE=C:\nDV\QM.SYS ROM=C000-C7FF X=D800-DFFF I=B000-B7FF I=C800-D7FF
I=F100-F5FF I=F700-F7FF RAM HA=256 ROM=F800-FFFF

ROM=C000-C7FF maps my VGA video card ROM to RAM to speed it up.
X=D800-DFFF excludes my Lantastic Network card ram so it will function.
I=B000-B7FF remaps memory that would normally be used for a Mo


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