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Thread: Weird Unisys 486 DX/2 EISA board

  1. #1
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    Default Weird Unisys 486 DX/2 EISA board

    Hello!
    A local seller has some interesting cards for sale and one of them stood out as it is an old Unisys that i haven't seen before in an Unisys or ALR system. It is labeled Unisys IOPIIE and it has a 486 DX/2 66Mhz CPU on it. It looks like a SBC but i'm not sure since it doesn't have any mass storage options on it so i'm guessing is one of those CPU modules that you can upgrade...
    The only thing that comes up on google is yjfy's site: http://www.yjfy.com/Museum/net/EISA.htm
    I've attached a picture of the card in question. The seller's picture is way worse than the one on yjfy.com .
    I would like to buy it but i would also like to use it and have no idea what system it came from.
    Does anyone recognize it?
    Many thanks,
    Andy.
    Attached Images Attached Images

  2. #2
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    My guess is that this is the CPU card intended to be used with a passive EISA backplane. The 2 ports are probably for display and keyboard. Other slots in the backplane would have contained your disk controller and other I/O cards.

  3. #3

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    There is a standard for PCI/ISA backplanes that use the EISA connector with both the ISA and PCI signals on it. Like the one here:
    https://www.directindustry.com/prod/...95-769109.html

    So it *may* not be EISA.

  4. #4
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    The link in the original posts lists the part numbers of the major chips:

    http://www.yjfy.com/Museum/net/EISA.htm

    from left to right intel S82353 / intel S82353 / intel KU82359A2 / intel A82380-16 / intel A80486DX2-66 / intel NG82355 /
    IDT 7025-S35J / CIRRUS LOGIC CL- CD0003-08PC-B

    Some of those chips appear to be EISA bus related, and none of them appear to be PCI bus related.

  5. #5
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    The 82355 is a BUS MASTER INTERFACE CONTROLLER (BMIC)

    That looks like something that is used on an EISA bus expansion board, and not something that would be the EISA bus controller. Maybe this is some sort of coprocessor board, and not the main CPU of a system?

    Intel Peripheral Components 1994, Page 1-576
    www.bitsavers.org/components/intel/_dataBooks/Intel_Peripheral_Components_1994.pdf

    1.0 INTRODUCTION
    The 82355 Bus Master Interface Controller (BMIC) is
    a highly integrated Bus Master designed for use in
    32-Bit EISA Bus Master expansion board designs
    and supports all of the enhancements defined in the
    EISA specifications required for EISA bus mai!ter applications.
    The BMIC provides a simple, yet, powerful
    and flexible interface between the functions on
    the expansion board and the EISA bus. With the
    help of external buffer devices, the BMIC provides
    all EISA control, address, and data signals necessary
    to interface to the EISA bus.

  6. #6

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    Could it be a hardware server monitoring/remote console? The link to yjfy.com suggests it is a network card, and the BMIC chip suggests it runs as a peripheral to the main system (used the BMIC chip on the Compaq EISA IDA card). Sure seems a little beefy for just a networking card, and with a VGA? There is a Unisys patent showing something similar (but an i960 CPU): https://patents.google.com/patent/US6732067

  7. #7

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    IIRC, somewhere in the datasheet, the BMIC can be used as a kinda turn-key solution for ISA devices as well as EISA. Basically "take the ISA design, cram our chip in-between, hay-presto EISA card. So perhaps, they just used it for the VGA or whatever.

  8. #8

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    Is there any chance this is from an Unisys U6000 system?

  9. #9
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    Quote Originally Posted by mR_Slug View Post
    There is a standard for PCI/ISA backplanes that use the EISA connector with both the ISA and PCI signals on it. Like the one here:
    https://www.directindustry.com/prod/...95-769109.html

    So it *may* not be EISA.
    That's PISA Bus from Kontron:

    https://www.kontron.com/downloads/wh...?product=87222

    It might be PISA, but PCI was barely ratified when 486s were common. Though this could be an older design (from the age of the 486's perspective) adapted for PISA. Most PISA boards started late Pentium going forward. You can almost count the 486/PCI chipsets on one hand and I don't see any of them on this board. Instead there are FIFOs and PLDs near the connector. I'm guessing it's EISA.
    "Good engineers keep thick authoritative books on their shelf. Not for their own reference, but to throw at people who ask stupid questions; hoping a small fragment of knowledge will osmotically transfer with each cranial impact." - Me

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