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Whats the word on 286 accelerator boards

30-28630-286
edited April 2017 in Hardware
So I have a IBM PS/2 model 30-286 (whoa! what a surprise :D ) and I'm looking for options to ditch the 10MHz 286. I've seen some 16-bit ISA cards that are a complete 386-system-in-one, 16-bit ISA cards that are just a 386, and daughterboards that fit into the socket that add a 386SX. Am I limited by compatibility or are all of these viable upgrade paths?

Comments

  • vbdascvbdasc
    Yes, there are some incompatibilities between 80286 and the later CPUs, that might surface, for example, when using some obscure 80286-era operating systems (some UNIXes, and even OS/2 1.x). For example, a subtle difference between 286 and 386 segment descriptor semantics, or the 286 LOADALL instruction, which is not present in 386 and later.

    http://www.os2museum.com/wp/theres-more ... nix-story/
    http://www.os2museum.com/wp/loadall-strikes-again/
    http://www.os2museum.com/wp/himem-sys-u ... d-loadall/
  • 30-28630-286
    Couldn't this be mitigated by installing 386 oriented software? The only hardwired software is the PS/2 BIOS and I expect that IBM wrote a one-size-fits-all solution for the 8086, 80286, and 80386.
  • IconIcon
    Kingston made a couple of 80386SX upgrade chips that fit 286 PLCC and PGA sockets. I have one (PGA variant) installed in a PS/2 model 50Z. There are few of these chips floating around on Ebay, but they come with a premium price tag.
  • 30-28630-286
    Just found one, this is exactly what I want. Thank you.
  • vbdascvbdasc
    30-286 wrote:
    Couldn't this be mitigated by installing 386 oriented software?

    Yes, and in fact, most software should work without problems. Although I would avoid older DOS versions, especially these from IBM.
    30-286 wrote:
    The only hardwired software is the PS/2 BIOS and I expect that IBM wrote a one-size-fits-all solution for the 8086, 80286, and 80386.

    I'm not quite sure of that. 8530 was a special type of beast - a low end one, and not expected to go beyond 286. IBM assumed in their OSes released during the late 1980s that all 386 (or newer)-based computers would be MCA-based, and it's quite possible that their BIOSes were the same.

    By the way, the only potential BIOS compatibility issue I'm aware of is the 286 LOADALL emulation, which is present in most (all?) 386-specific BIOSes for AT compatibles. A BIOS for 286 AT-class machine has no need of such feature and will most probably not support it.
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