Concurrent DOS/386

Concurrent DOS/386

Concurrent DOS/386

Concurrent DOS/386 was a successor to MP/M, from Digital Research.

I’ve been able to track down a few versions:

  • version 2, released November 17, 1987
  • version 3, released February 23, 1988

What is interesting is that these versions include a CP/M 8086 emulator. I would imagine that would be a ‘big deal’ for users of the older MP/M to migrate into a newer 80386 environment. From what I’ve seen in other places these were compatible with MS-DOS 3.0 . It can also read extended dos partitions! Since they predate VCPI/DPMI there is no way to run protected mode applications. Concurrent DOS/386 is later followed up with Digital Research Multiuser DOS. It is interesting, well to me that DR-DOS was basically a single user, single tasking version of the Multiuser DOS.

Multiuser DR-DOS

I was able to install this on Qemu 0.13.0. Although this includes some IPX/SPX stuff from the later purchase of Digital Research by Novell, it still remains a largely MS-DOS 3.3 compatible OS. Because it uses protected mode, and the v86 mode, it is still incapable of running VCPI/DPMI programs. Also absent is the CP/M emulator. I think there was a DR-DOS 6 equivalence sold as a multiuser, but by the time of DR-DOS 7, the product had been forked and several VARS started to sell their own versions based on Multiuser DR-DOS. These included (but probably not a complete list)

  • REAL/32
  • System Manager
  • DR-Multiuser-DOS

Of these, REAL/32 seems to be the only one that is still alive, and being sold by Intelligent Micro Software. I’ve located a demo version of REAL/32 here.

REAL/32 logo

REAL/32 certainly feels a lot like DR-DOS (which it is derived from) and what is cool is that it supports DPMI applications. I’ve tested some Borland Pascal stuff, along with DJGPP. Like the others it supports serial terminals to be hooked up.

real32 serial connection


Qemu makes it super easy to simple to switch to the serial port, and bring up the ‘second user’. I’m pretty sure you could use qemu to redirect it’s serial port over TCP…

And speaking of networking, the install program also seems to have some kind of networking config built in, so I would imagine each VM can have it’s own IPX/SPX setup? I’ll have to mess some more with it.

If you’ve ever liked DR-DOS, you may want to give real/32 a whirl, it’s certainly more… interesting.

8 thoughts on “Concurrent DOS/386

  1. You got me to dig out my qemu and 386-dos disk images. I am able to boot the floppy but I cannot seem to get it to install – have you had any luck with installing the 1987 version in anything?

  2. A previous office ran Novell MultiuserDOS 7.1. We ran the OS on a then top of the line 486 PC compatible, and had serial terminals connected to a Digiboard PC/X.

    We ran a terminal emulator in Windows, and ran a DOS programs (WordStar 7.0 & WordPerfect & Timeslips DOS.) Multiuser DOS would essentially open a “DOS session” for each terminal and an instance of whatever DOS program. The OS would also run CP/M-86 software, and the senior partner insisted on running WordStar CP/M on a Televideo terminal. Users could share the “C:\” drive, but there was also built in Netware support, and each user could access a share drive, in our case, a Netware emulator on a Linux box. The share drive was also then available to other machines, using other network protocols. The OS was very stable and reliable.

    You need a standard IBM compatible PC. You also need Multiuser DOS. Version 7.0 required a dongle. 7.1 did not. I have the set of 5.25″ floppies and the dongle.

  3. Sorry, pushed comment to soon. I don’t have the box or the user guides, and there were several updates and patches I downloaded from Compuserve. Also, the version was 5.1, not 7.1.

  4. Yep, even REAL/32 still had CP/M-86 app support. When they added FAT32 support, they still had to support FCBs for these apps, making DOS FCB support almost free (unlike MS-DOS which ditched FCB support almost completely with FAT32!).

Leave a Reply