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Any opration system which runs on an i860 CPU in a 486 system?

1ST1

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There were a few 486 mainboards where an i860 could be installed, Olivetti LSX 5010/5020, CP-486 and M480, Hauppage 4860 mainboard for example. Is there any operation system which is able to use the i860 processor on such a system?

I have already checked, my result is until now, no. Wikipedia says that Microsoft originally designed to run Windows NT on the i860, but after testing it not only on emulator, but on real machine, they dropped i860 support as it was unexpected slow. I also checked the last year leaked source code of Win NT 3.5 and NT 4, there is no i860 tree. Also install ISOs for NT 3.1 habe no i860 directory (but 386, alpha, mips, ppc, ...) It also looks like if Linux never was ported to the i860 platform, what is surprising as "they" usually got Linux running on anything.

i860.jpg
Njamnjamnjam....
 
Even if there would be an OS for it (there isn't), you would not be able to use it. On your Olivetti, the i860 is used as a math co-pro (non-standard like a Weitek) and can not act as the main CPU.

Afaik the i860 only saw uses as a co-pro, and on graphics cards and SCSI controllers.

//edit:
English Wikepedia states there was UNIX System V/i860.
 
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That mainboard is designed for the i860. It's not just a coprozessor. That mainboard has 64 Bit RAM bus for the i860, full access to this memory and EISA bus. The i486 uses a kind of interleaving ("Raid 0") to the memory. The mainboard can switch between i486 and i860 operation by software. I can tell you, as I have the documentation ("Theory of operations", service manual, etc.) for that mainboard, and I have a Windows 3.11 driver for the EVC-1 EISA VGA card which can use the i860 for acceleration.

Is UNIX System V/i860 available somewhere?

i860-1.jpg i860-2.jpg i860-3.jpg i860-4.jpg
This are some pages of the documentation of these machines which show that i486 and i860 are sharing the whole computer ressources.
 
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and I have a Windows 3.11 driver for the EVC-1 EISA VGA card which can use the i860 for acceleration.
Exactly, because acting as a co-pro for stuff like that is the whole purpose of the i860 on that board.

No idea why you conclude that the i860 can also act as the main CPU only because it has access to the bus and memory.

But anyway, track down a copy of UNIX System V/i860 and see if it works. :)
 
If it is possible, that means it is useable. But that does not say anything about if it is usefull. There are explains in Internet that i860 was not a usefull general purpose CPU as it was slow for example in context /task switching, but anyhow, if there is an easy way to try this, I would try it. Our whole hobby is unusefull.
 
was intended by the original designers.

The very sketchy info that's out there for the board does explicitly say they intended an i860-centric UNIX to be able to run on it, so I guess that counts as intention. I'm mildly curious about the gritty details, like if the 486 was intended to just "go to sleep" or if it would have retained an active role as an I/O processor or whatever, but it looks very much like the product was in the end complete vaporware.

It looks like, as mentioned, the only "useful" thing they ever figured out to use the i860 on in the real world for either the Hauppage board or the Olivetti machines was for acceleration of an otherwise "dumb" VRAM video card. I do wonder, though, if any development tools for these systems ever leaked out into the wild and are stashed on the internet somewhere. It's not a whole OS but it might still be mildly amusing, assuming the tools exist, to partition up the system and compile some kind of demo to run on the i860. (Maybe a mandelbrot set generator or whatever, a thing that might at least in theory show off its calculating grunt.)

The sad fact, though, is the i860 kind of deserved to fail. It was *very fast* under *very limited* circumstances, without hand-tuned code it ran like garbage and consequently was a pretty bad general purpose CPU. That's why no Linux port exists. (That and the sheer rarity of the hardware.)
 
on in the real world for either the Hauppage board or the Olivetti machines was for acceleration of an otherwise "dumb" VRAM video card

Yes, I have a driver for the Olivetti EVC1 EISA VGA card based on an S3 chipset to do exactly this in Win 3.11. Never tryed until now, as I did not had an i860 chip when I used the machine 20 years back in time regulary. I will try this as soon as the board is running relible and stable, need to change some capacitors.
 
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