I think that Compupro supported multiple 8086 cards and there was customized variant of MP/M-86 or its successor DR-NET that could handle the multiple CPUs. Other OS options were possible but probably needed a bit of customization to match the specific set of cards in a given Compupro.
"Multiprocessor" is a rather nebulous term. Do you mean SMP-type where both CPUs are running at the same time, sharing the same memory? Or the case where only one CPU at a time is running at any one time, or the case where each CPU has its own memory?
The 8089 was supposed to solve the rather kludged-up DMA issue of using an 8085 part (the 8237) for 16-bit DMA. It had a 20-bit address bus and register set, but the cost, coupled with the requirement for its own programming/ROM never made it very popular. The 80186 could already do 20-bit address DMA in either 8 or 16 bits, so there was no need for it in the embedded market. By the time the 80286 was released, the 8089 was a dead duck--it lacked the extra 4 bits of the 286 physical address bus--and traditional 8237-style DMA was becoming less popular because of the rise of bus-mastering DMA and falling memory prices (each peripheral could have its own memory).
Pretty much born an orphan. I remember the Intel sales guy wrinkling up his nose when I asked about it.
I bought What I believe to be a 4 port high-speed serial card off ebay a while back. The darn thing had a 4mhz 80286 AND a 6mhz 80186 on the same card and it appeared to have 4Mb of ram. Quite an insane card if you ask me. I ended up putting it in some box and it sits on my shelf. While its not "smp" or "multi-processor" in the conventional sense. Its still pretty awesome.
Pic 1: The front view
pic 2: Closeup of the serial port controllers. 2x D8274 1x P8253-5
pic 3: closeup of processors left to right, C8207-2, C80186-6, C80286-4
pic 4: backside
pic 5: The memory. each simm? has 4x mostek MK4564E-20 (64k x 1)
not pictured is the dongle cables. They connect at the card via 2x9 header connectors and split into 2x female db-25 connectors.
Hi! John and I are working on an S-100 8086 CPU board which supports the IEEE-696 multiple bus master logic. I think at least in theory two or more of these boards could be installed on an S-100 bus to form a multi-computer. Each CPU would run its own instance of MS-DOS, FreeDOS, or CP/M-86 though. John is already running the prototype board in tandem with the S-100 Z80 CPU board so this seems at least plausible. I am not sure if this is what you are asking about though.
I went back in my paper files and found my notes on "competition"--I was consulting for another company making an 80186/80286 box--and found the company name "PC Technologies". Armed with that, it was a matter of a simple Google.
FWIW, the 1987 sales numbers for the thing were only in the double-digits. So not really popular.
So have I got it right that this card, with it's MB's of RAM and two full processors, enabled an XT to be accessed from four terminals concurrently for presumably text-mode DOS apps?
Their original plan was to market the thing with 286 Xenix, but I don't know if that ever happened. AFAIK, they only offered DRI Concurrent DOS. But yeah, 4 terminals + the XT native = 5 users.
OTOH, we did offer Xenix for the Poppy II and, in fact, based all our applications on it.