I know there are people working on a 386 version of FreeDOS or
something like that, but I have something that in a way is a more
modest idea.

I wonder if people today have forgotten the multitasking
DOS-compatible OSs of the 1980s? First was Digital Research's DOS+,
which was CP/M-86 modified to make it slightly more MS-DOS-compatible;
it supported background tasks. In a parallel line there was also
Concurrent CP/M, a multitasking version of CP/M-86 that supported
multiple users on a single PC with dumb terminals attached to the
serial ports. You could also run 4 tasks on the console, using a
hotkey to switch between full-screen virtual consoles.

Concurrent CP/M offered very limited MS-DOS compatibility; it could
run safe, command-line DOS apps, not a lot more. It evolved into
Concurrent DOS, which could multitask multiple DOS apps, and that
evolved into Concurrent DOS/386, which used the v86 mode of the 80386
chip to provide safer, hardware-multitasked DOS VMs.

CDOS386 later evolved into IMS Real32 and if I remember correctly
something called Flex32 from another company.



There were others along similar lines: TSX32, PC-MOS/386 and others.



The snag with them is that because they had a different kernel, a
386-mode one, they were incompatible with MS-DOS device drivers and so
on, including things like network stacks.

I am concerned that the same problems might hamper any 386 version of FreeDOS.

But there was, I thought, a promising line of development in DOS in
the early 1990s that never happened, killed off by Windows 3. It was
DESQview/X: trying to bring a degree of Unix and X.11 compatibility to

DESQview was brilliant, bringing pre-emptive multitasking to DOS. Run
it on a 386 with QEMM386 and it delivered v86-mode hardware
multitasking, with multiple 640K VMs running happily on a 4MB 386 PC.

DESQview/X replaced the text-mode front end of DESQview with X.11, the
windowing system from Unix. It came with a choice of window managers –
Quarterdeck's own and Motif, if I remember correctly.

The big advantage of DESQview was that it ran on top of vanilla DOS,
so you could configure your standard DOS network stack, CD drivers,
mouse drivers, etc., all in the usual way, then launch DESQview on top
and all the VMs inherited the drivers from the base system.

DR-DOS is open source and has a multitasking task manager, I believe.
It's fairly basic but it's out there and it works. There were also
hooks to control it from ViewMAX, the special cut-down GEM that
shipped with DR-DOS 5 and 6.

There was also a similar environment for the Atari ST called MiNT,
which brought Unix-style multitasking to the ST's CP/M-68K derived OS.
This was open source, too.

What I'd love to see, more than a 386 version of DOS, which probably
wouldn't work with existing device drivers and so on, and might well
be no use for BIOS flashing and other purposes like that, would be a
Free recreation of something like DESQview/X.

Step one, a Free multitasker for DOS that delivered something close
enough to a Unix or Linux API that it might be possible to port some
Linux tools to it.

Then, perhaps, use Linux code and tools to upgrade this to the level
that it could run XFree86.

There are a lot of programs and tools supplied with FreeDOS. Its
utility would be much improved if they all could be multitasked, even
if on a full-screen basis.

Not all of this need be re-invented from scratch – there is Free code
out there that could be used, or at least studied. It would be a
bootstrapping process, as once the system got to a level where Linux
tools could be cross-compiled, there is tons of suitable Free software
available: lightweight window managers, editors, Internet tools and so

Liam Proven • Profile: http://www.linkedin.com/in/liamproven
Email: lpro...@cix.co.uk • GMail/GoogleTalk/Orkut: lpro...@gmail.com
Tel: +44 20-8685-0498 • Cell: +44 7939-087884 • Fax: + 44 870-9151419
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MSN: lpro...@hotmail.com • ICQ: 73187508

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