On 6/28/2016 11:08 AM, Eric Auer wrote:
> Hi Abe,
>> Based on Eric's suggestion of using more cautious settings,
>> I found the JEMMEX doc page
>> (http://help.fdos.org/en/hhstndrd/base/jemmex.htm)
> The documentation is also included in your installation on disk.
> You could also try X=TEST Without I=TEST, but excluding C900 to DFFF
> seems to be an even more cautious choice for your specific system.
Doing that results in an additional message before crashing so it looks 
like I will have to stick with the specific exclusion.

The additional message:
Warning: no suitable page frame found, EMS functions limited.

>> Boot option 1 no longer crashes, but it doesn't appear to be an
>> improvement over boot option 2...
> Option 2 loads SHARE and uses HIMEMX together with JEMM386 instead
> of JEMMEX which combines "HIMEM" and "EMM386" into a single driver.
> Option 2 also moves the PCNTPK network packet driver to UMB, which
> is why you have slightly more "largest executable program size" in
> option 2 compared to option 1 in spite of option 2 loading SHARE.
> You can try using LH for PCNTPK, but if you do not use internet in
> DOS, you could simply comment out the whole line that loads PCNTPK.
> If you only use EMS-aware software which is EMS 4.0 compatible,
> you can disable EMS 3.2 compatible page frames with some option
> for JEMMEX and JEMM386: That way, you get 64 kB extra space for
> UMB use, so it will be easier to LH things and gain low space.
> I think today EMM386 is more often used for UMB and less often
> for EMS. If you only use UMB but do not need EMS at all, you
> can also disable EMS 3.2 compatible page frames, of course :-)
>> Boot option 1 (http://tinypic.com/r/zm1boj/9): [JEMMEX]
>> Total memory Free: 26,699K
>> Total Expanded (EMS): 8,576K
>> Free Expanded (EMS): 8,192K
>> Largest executable program size: 597K
>> Largest free upper memory block: 2K
>> Boot option 2 (http://tinypic.com/r/2zzjl77/9): [HIMEMX+JEMM386]
>> Total memory Free: 26,669K
>> Total Expanded (EMS): 31M
> Interesting that JEMM386 defaults to offer more EMS than JEMMEX.
>> Free Expanded (EMS): 25M
> Odd, what happened to the other 6 MB of EMS?
I was wondering that myself...

>> Largest executable program size: 610K
> This is because that option loads SHARE & network drivers high.
>> Largest free upper memory block: 4K
> This is interesting: In spite of loading more things into UMB,
> you have more UMB left. That MIGHT mean that option 2 does not
> have the X=C900-DFFF option but still is lucky enough to avoid
> a crash? It could already be unstable, though. Maybe it would
> still crash as soon as you use the network in DOS.
Right, I didn't block that region in option 2. I used networking with 
option 2 to install the VBOX-FIX COM patch earlier. I didn't experience 
a crash. Perhaps I was "lucky". What's interesting is that there is no 
delay loading the UIDE driver so maybe Oracle has fixed the bus scan 
problem with VirtualBox rendering the patch unnecessary. Perhaps someone 
else can duplicate these results and confirm.

> ALSO, the option 2 takes the "dangerous" step of explicitly
> including the monochrome graphics card text memory area as
> UMB memory (I=B000-B7FF). This means that attempts to use a
> program which uses monochrome video modes may cause crashes.
> It could also be the real reason why more UMB is free there.
I was going to use option 2 even after all of this, but I will remain 
with option 1 now that it works; especially since you have indicated 
twice now that option 2 might be unstable. Thanks for that insight.

> I think that even 597 kB of low DOS memory is plenty for old
> DOS programs. New DOS programs use a DOS extender anyway, so
> they will be able to use your EMS and XMS, which are several
> megabytes. You can use other MEM command line options to see
> more details. Check the output of "MEM /?" to learn more :-)
> Regards, Eric
> PS: Do you use a special MOUSE or the usual CTMOUSE driver?
I have not installed a mouse driver or configured the mouse in any way. 
My AUTOEXEC.BAT has the standard "MOUSE" command in it.

> PPS: I see 1.1 uses XMGR in option 3 and 4DOS in option 4,
> not sure if those are included in the 1.2 distro any more.
For the record it looks like 4DOS is also in option 3, but thanks for 
the info. It's apparent that a well written book might help me come up 
to speed on all of these memory modes and managers. My interest is in 
programming anyways (I'm new to DOS but not programming). Any suggestions?

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