VOGONS


First post, by Gahhhrrrlic

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There is apparently a daughterboard that permits an ordinary FPU socket to accommodate BOTH an x87 coprocessor AND a Weitek processor, so that you can have super fast single precision math and your trig functions, etc. As I understand it, computers were able to use both simultaneously with no problem. The issue was that the sockets themselves were usually not designed to accept both at the same time but only 1 or the other.

I can't seem find a physical example of one or one that I could buy though. I'm not sure what to google but I've tried different guesses. Anybody know what these things are called or where to get one? I want to couple a Weitek with an IIT on my 386.

https://hubpages.com/technology/How-to-Maximi … -Retro-Computer

Reply 1 of 9, by mpe

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It is not completely unfeasible as the Weitek 3167 is a memory mapped-device which appears to CPU as a block of memory (unlike stack based x87) . However, it would probably have to be a local-bus device as it is a 32bit device sitting on COOOOOOO and VL-Bus wasn't very common on a 386. I've never seen one any such adaptor.

Many early 486 boards have Weitek 4167 socket and thus when using 486DX CPU you that way you can have internal x87 FPU and external Weitek FPU. But it is probably not worth of hassle as Weitek is not that much faster and hardly supported by software or even compilers.

Last edited by mpe on 2021-01-14, 09:53. Edited 1 time in total.

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Reply 3 of 9, by mpe

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Or that.

You can try to call them quoting the part number 😀

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Reply 4 of 9, by Gahhhrrrlic

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That DOES seem like what I was talking about. Wow. I'll have to see if I can hunt one down.

So I guess any benefit from either chip has to be due to specific instructions being called by the software? Otherwise it does nothing?

https://hubpages.com/technology/How-to-Maximi … -Retro-Computer

Reply 5 of 9, by wiretap

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I found something similar on Ebay the other day, but it was an accelerator card for an IBM XT. It can be found by searching for: "Univation Inc PC Turbocharger PC Accelerator Card (1984) RARE"

It may be of interest if you're into these types of FPU boards.

Circuit Board Repair Manuals
Turbo Display Project
Dual Socket 8 Project

Reply 6 of 9, by Anonymous Coward

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That isn't an FPU board, though it is pretty interesting. It's a 10MHz CPU upgrade card with dedicated memory (almost an SBC), though it looks like it might be missing the cable that goes to the CPU socket.

It's also unclear if it uses an 8086-1 or an 8088-1. (or maybe even an 80186, the picture is too blurry).

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Reply 7 of 9, by PC Hoarder Patrol

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There's this pic of the actual beast (or similar) from an ad in a 1990 NASA Tech Brief

Weitek DBrd.jpg
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Weitek DBrd.jpg
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345.09 KiB
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107 views
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Fair use/fair dealing exception

and the same, but this time with just a Cyrix FasMath

Weitek DBrd - FM.jpg
Filename
Weitek DBrd - FM.jpg
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122.52 KiB
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107 views
File license
Fair use/fair dealing exception

Reply 8 of 9, by Gahhhrrrlic

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That is awesome. This must be some sort of museum piece they only made a handful of because I can't find any trace of this product beyond the aforementioned. This is the sort of thing that would make you stand out at a retro computer convention if you had one.

https://hubpages.com/technology/How-to-Maximi … -Retro-Computer

Reply 9 of 9, by Jo22

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I think I saw such a daughter board in an old magazine, too.
From what I remember, the Abacus series was made for both the 386 and 486.
So there may chips with different pinouts.
But since I don't own one, I'm not sure.
Best I did in this context was trying out the demo programs in x87 mode.
https://www.youtube.com/watch?v=RagZa9AxXqE

What I also remember is, that the Weiteks require an utility, like EMM386, in order to work.
But then, you loose Real-Mode compatibility and a bit of performance due to V86 (on 386 and early 486 only).

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