On Fri, 28 Jun 2013 06:09:54 -0400, Trent .****off
wrote:

On Thu, 27 Jun 2013 16:44:26 +0100 Rui Sá wrote
in Message id: :

On Fri, 21 Jun 2013 13:07:38 -0700 (PDT), wrote:

Hi, I got a broken old pc. It is a challange to fix it for me. There is a hdd with an unix system and with a special software. it is a parth of a machine for industry. It seems taht thw sw is connected with a hardware on the computer.

I am looking for details information about this motherboard

http://i40.tinypic.com/2lmmfiq.jpg

Yes, it is little bit out of date. Does anyone know a detailed information or a shop who can sell this type of mb?

There's a Cyrix CX-83D87-33 math coprocessor (compatible with Intel's
80387) on that board, so I'd say it's an i386 mobo, running at 33 MHz.

Can't be - if you magnify the empty socket you'll see it's marked socket 3
which was for the i486.

Yes indeed, it's a 237-pin socket, which is not compatible with the
i386, which has 132 pins.

However, what's the Cyrix CX-83D87-33 coprocessor doing on that board,
as I don't think it's compatible with any 486 CPU: the i486DX included
its own FPU (faster than the 80387) so there won't even be a socket
for a coprocessor on its motherboard.

The cheaper i486SX lacked the FPU and some boards included a socket to
add a math coprocessor later but AFAIAA it was only compatible with
the i487SX, which is the same size as the i486SX itself.

This board not only has a socket for a coprocessor (which means it
came with an i486SX), but it's smaller than the i487SX socket and has
installed an 80387-compatible FPU and probably some special logic to
make it work (asynchronously?) with the i486SX, making it clearly
slower than a full i486DX for FPU operations. Were the savings worth
the effort, the extra logic and the slower FPU speed?...


[...]
What do you make of that weird slot?

That's most likely a VLB slot (VESA Local Bus):
http://en.wikipedia.org/wiki/VESA_Local_Bus

The left part is just an ISA slot. This was a very popular slot for
video cards before PCI became common, specially in later 486 systems.


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