PC-MOS/386 print ad

PC-MOS/386 print ad

PC-MOS/386 was another multi-user MS-DOS Operating system. And they had some great ads, like above.

I was able to track down a few disks but of them all only the version 5 one seemed to run to some degree under Qemu. Or at least the $386.sys memory driver.

pc-mos 1.02

pc-mos 1.02

This is about as much as I got out of PC-MOS/386 1.0

pc-mos 3.00

pc-mos 3.00

While PC-MOS/386 3.0 loads, if you try to load the protected mode $386.sys driver it just hangs.

pc-mos 5.01

pc-mos 5.01

And PC-MOS/386 5.0 not only loads, but will load up with the protected mode driver on Qemu.

pc-mos 5.01 protected mode

pc-mos 5.01 protected mode

I’ve managed to get a serial ‘terminal’ to run, and for anyone who ever needs the hint, here is the config.sys, autoexec.bat and user01.bat file to make it boot up…. Neither VirtualPC, nor VMWare can boot up with the drivers.


memdev = \mos\$386.sys /p
device = \mos\pcterm.sys
device = \mos\$serial.sys /ad=03f8,in=4,hs=x,ib=2048,ob=2048
smpsize = 80k
buffers = 40


echo off
rem turns dot prefix command syntax off
rem issue path command
path c:\;c:\mos
rem configure for terminal(s), each addtask line is for a terminal…
addtask 300k,1,,user01,pcterm,1,19200
rem addtask 300k,2,,user02,pcterm,3,19200
rem addtask 300k,3,,user03,pcterm,4,19200
rem addtask 300k,4,,user04,pcterm,5,19200
rem set up printer
addtask 032k,6,,printer
rem make print spooler directory, note this example uses a
rem virtual disk.
rem md d:\spool
rem issue command for spooler
spool c:\spool\ /t05
rem define operating system prompt
prompt $h0$p $


path c:\;c:\mos
prompt $h1$p $a
spool c:\spool\ /t5

So what is it like? Under emulation lots of keystrokes are lost, and it feels slow. I’m sure it’s a COMPLETELY different story on actual hardware. PC-MOS 5.0 also cannot run DPMI programs, which is a shame. Then again DPMI was a ‘new and exciting’ thing in 1992 so I guess it’s not that surprising. I’m not aware of any support to run Windows 3.1 but again 1992 was when the tide really started to turn to Windows.

As they mention on wiki memory costs, and slow disks of the time certainly made things like PC-MOS really slow.

30 thoughts on “PC-MOS/386

  1. your 5.01 version, probably the one I made available online a few years ago! I have a 5-user, 9-user (think you're running that) and a 33-user, and with activation codes. Also have the troubleshooting guide, and get this, the Novell Gateway!

    As I recall, this one ticked Novell off, because I believe it only tied up (2) connections for the entire PC-MOS system. So, if you had a 33-user PC-MOS, with 33 users, Novell only saw 2 connections, so you could get by with the entry-level 5-user Novell netWare servers of the day.

    SOld and installed many PC-MOS systems in the day, and it was a good product. Worked great with Real World / Synchronics accounting.

    • Had a PCMOS/386 up and running until recently when the hard disk crashed.
      When I tried to re-install the OS from the original floppies, found that were unreadable.
      Do you know where I can find/download the disk images ?

      Thanks in advance

  2. Hi,

    I was a consultant & VAR (Value Added Reseller) for TSL (The Software Link) and their PC-MOS/386 products, from ’88 until ’94. I both used and installed this OS extensively in our own sw devlpt lab, and at client sites. We setup a lot of turn-key/point-of-sale systems, database apps which required multiple user stations. We nearly always used Wyse terminals (150, 50, or 60). It all worked great. This cut the cost considerably, in contrast with the corresponding ‘network solution’. Up until 2007, I had all of the sw, keys, manuals (in the nice binders) for the 5 and 9 user versions; but after more than a decade of not using them, I parted with everything – including my old i386 & i486 systems. How I now wish I hadn’t!!! But we were moving, departing with and selling everything possible (no room for extras). I’ve just recently started sharing the history of the legacy OSes with my son (who like me likes exploring computer systems and various OSes) and wish that I could show him some older “virtual machine” systems running various DOS versions.

    Does anyone know of anyway to obtain the full version of PC-MOS 5.1? I read that it has been place under a GPL of some sort, but the site(s) I’ve visited don’t have any binaries or source to download. We’re trying to put together a lab of legacy systems, and are interested in getting/running the following OSes:

    DR Multiuser DOS
    Concurrent DOS/386
    MP/M 86

    • I recently have been cleaning-out our attic and found my old copies of Multiuser Operating systems from the late 80’s to 1994. I found my. TSL Multilink, PC-MOS/386 various versions. PC-MOS Novell Gateway, PC-Emulink and associated Manuals. I’m thinking of running them all as virtual machines inside VMware, VirtualBox, or the open source XenServer. I also have the legacy hardware they use to run on. I have to try to resurrect these old PC that use to run these OS’s to save any info and SW drivers and documentation that are still in them. I hope these diskettes are all still good. I also plan to convert the manuals to pdf later on. I hope they’ll run as virtual machines on my HP servers one is a 32 bit DL580 G2 and migrate it to the DL580 G4 64 bit server. I figured these are at least 20 to 25 year old software and since TSL is no longer around it is considered abandonware and can be duplicated.

  3. the darn thing stopped 8/1/12 operating system died….any one know if there is some way of fixing it?????? thanks!

    • I used to debug and disassemble several multiuser systems from the 80’s and early 90’s. I found some of my hacking tools along with my copies of masm tasm and linkers. I may have to use these tools to try to see what’s going on. It will be easier with the source code of pcmos. But I have done it before without the source to patch several multiuser os and dos programs so that they run without directly writing to display memory. But that’s more than 20 to 25 years ago. I have more time in my hands now so I can refresh my memory on how i did it back then. Just need to rebuild my development system and operating system in that time period

  4. alguno de ustedes podria compartir la imagen del disco, necesito cargar pc mos y no lo encuentro por ningun lado, por favor

    • I’m trying to build a test vmware setup to load pcmos/386 out of diskettes I found while cleaning out my attic. (See my comment above.) What version of pcmos are you looking for? And what diskette format do you have?

  5. I have used PC-MOS extensively to set up turnkey systems for 20 years and many are still in use. The OS stopped functioning correctly at 8/1/2012. I used to be able to read a file with a Norton hex editor and correct a date code or other feature but in this case I have no idea what kind of date code in the OS file that I’m looking for. Has anyone been able to fix this kill date? and if so, could you share the fix process?

    • wow I’ve never heard of such a thing… there is still a market for multiuser MS-DOS systems? I was actually kicking around the idea of making one the other day but I figured nobody would care….

      Maybe I can do something… email me or reply here.. 🙂

  6. I still have the source tapes.

    I want(ed) to make it GPL and while I got an OK on it, I haven’t had time nor managed to get it legalized. E.g. lift the NDA and be able to publish.

    If and only IF it’s OK to do so, I will finally push the whole tree to github.


  7. We have used it for accounting in the 90-ties.
    A big compaq 386 with 5 green terminals.
    Cobol application, and worked like a charm !

    • it really was and still is cool.

      yesterday I agreed on the used license (GPL v3) and will add that to the repo. If that is in place I will start pushing all the code.

      Note that I also got a hold on the cdrom source code driver that is being used and will also be placed in th epublic domain under GPL v3.

  8. The date bug was fixed earlier this year and there are scans of the v4 documentation available in the repo. I also have release candidates out for testing. Check the wiki on Roeland’s page for more information.


    • PC-MOS/386 v5.02 has been released. No more date bug, no more 60 minute timebomb, added CD-ROM driver and more!

      Also v5 documentation has been uploaded to Roeland’s repo as well.


        • I do run it in my lab on some old 32bit AMD boards, P4 desktops, and a laptop in my lab with an old Wyse terminal to have a second session. Some of the systems have issues with the Memory manager when it goes into protected mode and some don’t. Other than that, it just runs.

          Most of my development and testing is done in DosBox and VirtualBox on Ubuntu. I have even set up a VirtualBox VM using 4 virtual COM ports and attached them to 4 minicom sessions on an Ubuntu VM for fun and to see how it all works. The security is interesting and the way it was implemented contributed to the disappearing files when the 2012 bug activated.

          Just recently I had someone reach out to me as his business is still running MOS and I patched his kernel for him. I was surprised to find someone still using it in a business environment!


          • When I first had Xenix running on Qemu I had so many small businesses and municipalities reaching out to me on how to rescue their systems. Naturally that fell off a cliff, as I hope that those tens of users were rescued and have since moved on, either migrating their data, or keeping it running in a VM forever.

            But never mistake it, if you have any kind of analytics loaded on a blog, you’ll find those lost souls from time to time looking up stuff. Back then I had wanted to do some kind of long term legacy support thing, but as always the trick is finding customers. Maybe I should have perused it harder, but I let that ‘full time job’ thing get in the way. I’m just glad I wrote the stuff down, otherwise I’d have forgotten most everything.

            I’m having what seems like PSU issues with that dual P3 board I recently got just before one of the big protests broke out. The electronic district here has been beset by constant protests & overwhelming police response so I haven’t been able to try to source a different and ‘larger’ PSU and or other legacy components. While I do have a single proc board, I’ve been hesitant on erasing it just yet to load that Mach386 thing I have going on. I’m really dying to know if it’ll boot on read hardware.

          • The AMD boards I use have dual processors. They are out of an old Linux Networx Evolocity I picked up years ago for my Minix Supercomputer project and MOS runs fine on that in Real mode. Being a DOS compatible OS, I am not sure if you could even wedge a second processor in there and have it function in SMP mode. It would be kind of cool though…

            Stay safe. Scary stuff in your part of the world these days.


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