I wish DOS had a better memory model above 640K

W

Wavelength

Bit poster
Gang,

In a typical dos setup above 640K you would have a block of memory for the video usually like 8K to 32K, Possible adapter memory block and then BIOS up on top.

This would leave holes for which EMS Page Fram could sit and also blocks for LoadHigh to place small drivers etc...

In the Parallels world there is no available space above 640K. It shows up like this:

Ax00: VIDEO RAM Usually open
Bx00: VIDEO RAM Typical video area
C000-C7FF: ROM
C800-CFFF: Adapter
Dx00: Adapter
Ex00: Adapter
Fx00: BIOS ROM

~~~~~~~~~

Parallels must use most of the upper area to do it's thing but really there isn't a need for that if they included a couple of drivers like they do in XP and other OS's.

My wish is upper memory support so that we can actually run programs.

Oh yea that and some support, but that is never going to happen.

Thanks
Gordon
 
Hairy,

My point was that Parallels takes up all the room above 640K making DOS well like so 1980ish.

If they take up all that area because of their drivers and etc then there is no place for EMS or high loading required for real dos apps.

Thanks
Gordon
 
One thing I've tried, with no success (unfortunately) is to "include" the disputed memory ranges on the command line for EMM386/QEMM. That's supposed to override it but then the VM doesn't boot.

What is the reason for pre-committing "ROM" space in the VM?

Oh, BTW, if you run "MSD" (Microsoft Diagnostics) from the DOS prompt, you get a slightly different view of upper memory:

A000-BFFF: "RAM" {Video of course}
C000-C7FF: "ROM" {same as below}
C800-EFFF: "RAM" {different!}
F000-FFFF: "ROM" {same}

So, I did a little testing. If you use the following, I get 159k of upper memory at c800 (resulting in 726k of free memory): device=emm386.exe noems i=c800-efff

Now, if you try to enable EMS by doing something like the following (... 2048 RAM i=c800-efff), it bombs out, complaining that it can't set the page frame address. If you use MEMMAKER, always answer "NO" to the question about programs needing EMS. After running MEMMAKER, I get the following:

Total under 1mb: 795k/69k used/726k free
Largest program size: 617k
Largest free UMB: 109k

I guess you need the right incantation. Can anyone from Parallels Support comment on the lack of EMS support?
 
Last edited:
constant said:
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I vote for Parallels personnel to not spend any time on trying to support such archaic technology.
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Click to expand...

Your opinion, of course, but I love working with DOS. Archaic, yes, but functional. I have several top-line systems with XP or Vista but having Parallels at my disposal saves me from having to dig out my Compaq DeskPro 386 to do some sort of "legacy" work.

I actually have several VM configurations setup for different things -- Windows 2000, Warp 4, DOS/Win31, plain 'ol DOS. I installed Norton Commander and Windows 2.03, too.

I have all of my favorite 80's music playing in iTunes...it's just like old times.
 
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