On Fri, Aug 4, 2017 at 6:01 PM, Tony Cappellini <cappy2...@gmail.com> wrote:
> Another data point...
> Before trying FreeDOS, I currently boot MS-DOS from a USB stick,

Which version of MS-DOS?

> with the following config.sys.
> device=himem.sys
> device=umbpci.sys
> FILES=40

That's a fairly low number, 80 might be wiser.


Do you need this? It's less useful if also using cache software.

> STACKS=16,512

This is very obscure, I hope you know exactly what you're doing here.


How much (low) RAM does this use? Of course FreeDOS has several
alternatives that may have smaller footprint.

> SHELL=C:\4DOS.COM /F /P /E:2048

/F for "always fail" may be unwise unless you're sure that's what you want.

> This gives access to most of the 4GB of RAM installed, even though I need
> more under 1MB. This is why I'm hoping FreeDOS and it's utils can help
> squeeze out more RAM under 1MB, or make more available above 1MB.

How much low RAM free do you actually need? What amount are you getting now?

> I'm still confused between UMB, EMS, XMS, Expanded and Extended memory.

You forgot DPMI!  ;-)

EMS = expanded
XMS = extended (286+)
UMBs usually come from EMM386 or UMBPCI (but personally I don't
normally need 'em)

Normally FreeDOS is pretty good about memory, so even on "XMS only"
setups, it shouldn't be any obvious problem (outside of extreme

Although I've already skimmed your later replies, my initial
impression still holds: don't worry about the details unless forced.
So unless you're absolutely sure that you need "more!", don't try to
fiddle with everything endlessly.

BTW, it has been discussed before about EMM386 pitfalls (and I think I
recommended that we shouldn't load it by default), but no consensus
was reached. Some modern machines are just buggy and EMM386 isn't
working well there. I seriously don't recommend using it unless you
really have to. (One guy did say using older, FD EMM386, not JEMM,
might help somewhat. You could also try freeware, third-party, EMS
Magic TSR.)

The README.TXT (from JEMM) says this:

 * If Jemm halts or reboots the machine, the following combinations
   of parameters may help to find the reason. Generally, Jemm386 should be
   loaded immediately after the XMM (HIMEMX.EXE, HIMEM.SYS), and the XMM
   itself should be the first device driver to be loaded. For testing, it
   might also help to prevent DOS from loading in the HMA and/or not to
   use UMBs at all.


     This is the safest combination. If this doesn't work, Jemm most
     likely isn't compatible with the current DOS/BIOS.

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