Multiuser DOS

This has been a fun thing to go through, but at one point it was a popular trend to convert big expensive 386 computers from the late 1980’s into multi-user, multi-tasking beasts much like a mainframe. But instead of CICS, and PROFS people ran Dbase III, WordPerfect, and all kinds of email solutions from ccmail, to MS mail, and even some dbase programs, compiled by clipper into being email clients.

In a way things were more ‘simple’ back then, and the 80386 CPU had a card up it’s sleeve v86 mode. v86 mode provides hardware emulation of a 8086, allowing the base OS to spawn dozens of these virtual machines. All that was up to the ‘supervisor’ was to create virtual peripherals, much like how Windows/386 of the day ran multiple MS-DOS VM’s on a single machine that you could see at once, these solutions provide the output to multiple terminals.

While Windows/386 sat on top of MS-DOS, these multitasking DOS’s had the v86 mode multitasking as part of it’s core, and some of the later ones were themselves protected mode operating systems.

But juggling multiple MS-DOS applications at one could be quite a challenge. And of course there was the whole dos extender thing, leading up to VCPI, and DPMI.

While MP/M-86 is a grand daddy to a bunch of Digital Research derived OS’s, it’s not 386 specific so I’m going to omit it for now. I’m sure it’ll be worth doing it’s own write up.

I’m sure I’m going to miss a bunch of these, but let’s have a quick rundown.

  • Concurrent DOS/386
  • DR-Multiuser-DOS 5.0
  • Real/32
  • TSX-32
  • PC-MOS/386
  • VM/386
  • VMOS/3

If anyone knows of any others feel free to give me a shout. It does seem that multiuser DOS was a good market at one point.

6 thoughts on “Multiuser DOS

  1. Just had to chime in on this one – I don't know of others, but I ran my business from 1991 – 1999 using PC-MOS with a mix of custom and off-the-shelf software on a 386 machine. I wrote my own email program in Visual Basic called "MosMail" At one point I had as many as 8 terminals running. It was a good system. I was able to preserve the software and I can still boot up the system in VirtualPC, but only in version 4 (prior to Microsoft, when it was a Connectix product). Wow, I miss that system…

  2. Qemu may be able to boot it…..!

    I have the feeling that there was quite a bit of these things out there… And some still remain. It sure is an interesting aspect of non Unix based Multi User systems for the 80386.

  3. My company still runs an MRP system on real32. In fact I'm trying to get in to run on VPC 2007 but having problems with the networking aspect.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.