The default QEMM config.sys line is "DEVICE=QEMM386.SYS RAM". If you are using
this config.sys line, you are playing with fire. On every system configuration
tested at Digital Dynamics, DESQview (or even just plain DOS) will eventually
crash using this config.sys line.

The problem is that QEMM is using memory regions that other components of your
systems are also trying to use. This is bad. QEMM may also not be using memory
regions that are not in use and therefore you may not be getting all the
available upper memory possible. This is important if you need to load TSRs,
device drivers, or network drivers into high memory to leave as much DOS base
memory as possible.

An example config.sys:

 1: shell=c:\dos\command.com /e:1024 /p
 2: stacks=0,0
 3: buffers=5
 4: files=50
 5: lastdrive=m
 6: device=c:\dev\qemm386.sys ram x=b800-c7ff i=f000-f7ff i=fd00-fdff
 7: device=c:\dev\loadhi.sys c:\dev\smartdrv.sys 1024
 8: device=c:\dev\loadhi.sys c:\dev\ramdrive.sys 4096 256 512 /e
 9: device=c:\dev\loadhi.sys c:\dev\ansi.sys

Remember, this example config.sys will probably NOT work in your system. It
does however work in one specific system. The right config.sys line for your
system will need to be determined by you. Keep reading to find out how to make
that determination.

Note line 6, where QEMM386.SYS is loaded. The extra parameters after "ram"
are specifying that QEMM exclude (not use) the memory region B800h through
C7FFh and that QEMM should include (use) the memory regions F200h through F2FFh
and F400h through F6FFh.

The "x=b800-c7ff" part of the line is VERY IMPORTANT. Without this parameter,
this particular system will eventually crash under DESQview or even DOS alone
under some circumstances. The crash will manifest itself differently with
different system configurations. It may give you a "QEMM protection violation"
or "Invalid instruction", or "NO ROM BASIC - SYSTEM HALTED", or it just may
suddenly freeze.

The "i=nnnn-nnnn" parameters in the line tell QEMM to include (use) these
memory regions for more available high memory. You should NOT use the inclusion
parameter unless you are positive that no component of your system will try
to use that memory region (including your system BIOS).

So how do you figure what to include and exclude? By using the QEMM.COM utility
with the "analysis" parameter. The first time you run "qemm analysis", you'll
see something like this:
 
 

The regions with the status "OK" mean that QEMM is dealing with it correctly.
It is either NOT using the region because another resource is using it or it
is using the region and no other resource has tried to use it since you booted.

The regions with the status of "Include" mean that QEMM is not using the region
and no other resource has tried to use it since you booted.

The regions with the status of "Exclude" (none listed above) mean that QEMM is
using the region and another resource has tried to use that region at the same
time. This region must be manually excluded with the "x=nnnn-nnnn" parameter
on your config.sys line.

Now don't be fooled by all the "Include" regions above in that box. As you use
the system, those regions will shrink, split, or disappear altogether. After
executing "qemm analysis" (producing the above output) and then accessing a
floppy drive, the "Include" regions already begin to disappear:

After switching into every available video mode and running "qemm analysis"
again:

After typing "echo ^g" at the DOS prompt (^g stands for Ctrl-G) and then
running "qemm analysis" again:

As you can see, just about every system function will effect the regions that
QEMM thinks you can safely include. It is a good idea to run just above every
application you can and access every device on your system before deciding
that the information provided by "qemm analysis" may be accurate and usable.

If "qemm analysis" every reports a region with the status of "Exclude", do not
question it. Immediately edit your config.sys excluding that region and reboot.

If, for example, "qemm analysis" reports:

Edit your config.sys file addding "x=f000-f1ff" at the end of your
"device=qemm386.sys" line. Then reboot your system.