[comp.os.msdos.desqview] The amazing vanishing memory trick

mju@mudos.ann-arbor.mi.us (Marc Unangst) (06/25/91)

I recently installed QEMM-386 and DESQview on my 386SX machine.
("Premio" motheroboard, with a VLSI chipset, AMI BIOS, 2MB of memory
on the motherboard and 2MB of memory on an Everex RAM 3000 Deluxe, set
up as extended memory.  [See below for explanation of why I'm using
the RAM 3000.])  Anyway, QEMM and DV both installed without a hitch,
and DV seems to be working fine.

However, there's a small problem.  When I look at Manifest's expanded
memory map, it shows that there's this 576K block allocated as
handle 0, with nothing in the "owner" column.  This was really
puzzling me, until I looked at how much memory I had free at the DOS
prompt -- 576K!  It appears that QEMM is grabbing some of the memory
and mapping it into the 0-640K space.  However, this shouldn't be
necessary, as I already have 640K of conventional memory.  Adding
NOFILL to the device=qemm386.sys line in my CONFIG.SYS didn't stop
this from happening.

This is somewhat annoying, since after my motherboard takes the 384K
between 640K and 1MB and hides it somewhere (no, it doesn't return if
you turn off BIOS and video shadowing), and QEMM takes 576K to map
over the existing 576K of conventional memory, I'm left with about
144K of expanded memory left.  This is why I'm using the RAM 3000,
which was left over from my old 286/10 machine -- until I can afford
to buy another 2MB of memory, slow memory is better than no memory.
(At least I can run a decent amount of stuff now.)

Does anybody know why this is happening, and maybe even a way to get
back that 576K?  Or is this an inevitable consequence of using
QEMM-386?  (And, as a side note, does anybody know how to get my
motherboard to relocate the 384K of RAM to somewhere over 1MB?  The
docs for my motherboard are sketchy; the only time that 384K is
mentioned is a paragraph that basically states that if you have 1MB of
memory installed as 4 256K SIMMs, you can relocate the 384K to just
above the 1MB line.  Do they assume that if you have more than 1MB of
memory, you'll have so much memory that you won't mind "losing" that
384K?)

--
Marc Unangst               |
mju@mudos.ann-arbor.mi.us  | "Bus error: passengers dumped"
...!hela!mudos!mju         | 

a_rubin@dsg4.dse.beckman.com (Arthur Rubin) (06/25/91)

In <kZB341w164w@mudos.ann-arbor.mi.us> mju@mudos.ann-arbor.mi.us (Marc Unangst) writes:

>I recently installed QEMM-386 and DESQview on my 386SX machine.
>...

>However, there's a small problem.  When I look at Manifest's expanded
>memory map, it shows that there's this 576K block allocated as
>handle 0, with nothing in the "owner" column.  This was really
>puzzling me, until I looked at how much memory I had free at the DOS
>prompt -- 576K!  It appears that QEMM is grabbing some of the memory
>and mapping it into the 0-640K space.  However, this shouldn't be
>necessary, as I already have 640K of conventional memory.  Adding
>NOFILL to the device=qemm386.sys line in my CONFIG.SYS didn't stop
>this from happening.

QEMM does that for me too.  It seems QEMM remaps low memory into expanded, as
well.  You aren't losing memory, it's just renamed.  (If it bothers you, try
NOSORT, and perhaps some other options to prevent QEMM from remapping low
memory).

--
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a_rubin@dsg4.dse.beckman.com (work)
My opinions are my own, and do not represent those of my employer.