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  • Re: Auction: Defective IBM 61X6752 Microchannel Memory Expansion Card w

    From WBSTClarke@21:1/5 to WBSTClarke on Mon Nov 29 18:10:14 2021
    On Tuesday, 30 November 2021 at 02:09:40 UTC, WBSTClarke wrote:
    On Saturday, 27 November 2021 at 21:23:01 UTC, Louis Ohland wrote:
    https://www.ebay.com/itm/265403130688

    BIN / MAO

    I'm not czeching on the particulars, but this card could not handle "18MB"

    Each SIMM has 9 OKI M41256, 256KBx1 DRAM. So, that would be 8 total
    256KB SIMMs, total 2MB?

    https://ardent-tool.com/memory/IBM_Memory_Expansion.html#1_8MB

    Is it truly defective, or is that they tried it inan incompatible system?

    Chances are that it works.
    Sadly, IBM had their own "presence detection" arrangement for 30-pin SIMMs of 256KB or 1MB capacity (with Parity and gold-plated contacts). So-called "Industry Standard" SIMMs will be mis-identified as to capacity etc.

    http://john.ccac.rwth-aachen.de:8000/misc/ps2cache/

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From WBSTClarke@21:1/5 to Louis Ohland on Mon Nov 29 18:09:40 2021
    On Saturday, 27 November 2021 at 21:23:01 UTC, Louis Ohland wrote:
    https://www.ebay.com/itm/265403130688

    BIN / MAO

    I'm not czeching on the particulars, but this card could not handle "18MB"

    Each SIMM has 9 OKI M41256, 256KBx1 DRAM. So, that would be 8 total
    256KB SIMMs, total 2MB?

    https://ardent-tool.com/memory/IBM_Memory_Expansion.html#1_8MB

    Is it truly defective, or is that they tried it inan incompatible system?

    Chances are that it works.

    Sadly, IBM had their own "presence detection" arrangement for 30-pin SIMMs of 256KB or 1MB capacity (with Parity and gold-plated contacts). So-called "Industry Standard" SIMMs will be mis-identified as to capacity etc.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Louis Ohland@21:1/5 to WBSTClarke on Mon Nov 29 20:29:37 2021
    Page 5 of the Mar 93 HMM has only a graphical depiction of the
    individual chips on a 30 pin SIMM.

    On 11/29/2021 20:10, WBSTClarke wrote:
    On Tuesday, 30 November 2021 at 02:09:40 UTC, WBSTClarke wrote:
    On Saturday, 27 November 2021 at 21:23:01 UTC, Louis Ohland wrote:
    https://www.ebay.com/itm/265403130688

    BIN / MAO

    I'm not czeching on the particulars, but this card could not handle "18MB" >>>
    Each SIMM has 9 OKI M41256, 256KBx1 DRAM. So, that would be 8 total
    256KB SIMMs, total 2MB?

    https://ardent-tool.com/memory/IBM_Memory_Expansion.html#1_8MB

    Is it truly defective, or is that they tried it inan incompatible system? >>>
    Chances are that it works.
    Sadly, IBM had their own "presence detection" arrangement for 30-pin SIMMs of 256KB or 1MB capacity (with Parity and gold-plated contacts). So-called "Industry Standard" SIMMs will be mis-identified as to capacity etc.

    http://john.ccac.rwth-aachen.de:8000/misc/ps2cache/


    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)