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(Posted this on HW Rec but got no responses.)

Would like to use an ISA expansion card in a modern PC. There are

  • Expensive PCI - ISA adapters (but I cannot find any actually for sale now)
  • USB-ISA adapters, which may not work
  • New motherboards with ISA slots, rare and expensive
  • Old motherboards for sale on Ebay
  • PCI to ISA bridge chips (eg IT8888G), but no products using them?

Are there no practical solutions to this problem? I cannot be the first person to want to do this.

Edit: when I say "modern" I didn't really mean the very latest. Am not sure what CPU I have exactly but it is around ten years old.

More: The card is an SCM Swapbox.

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    ARS Technologies still show the usb2isa-r USB 2.0 to ISA card as available. I used something similar (if not identical) in a legacy application around a decade ago. I hesitate to post this as an answer as some driver code will need to be written and your specific card may not work. The hardware is beginning to get into legacy/mission critical status, so solutions that work reliably tend to be expensive. These target industry, not hobbyists – scruss May 13 at 14:09
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    It would be helpful to know the details, if you have a specific project in mind. People here familiar with retro hardware and software could potentially offer numerous solutions to the problem of an obsolete peripheral controller / ISA card, other than making the card work directly in a modern PC with no ISA bus. – Brian H May 13 at 14:41
  • I was about to write the same as Brian above. There are hobbyist boards which can be used to rebuild XT-level PCs from scratch, with support for ISA cards, or you could use an ISA backplane with an S-100 converter and build a 486-based system... (But obviously that’s nothing like running a current CPU and being able to connect an ISA board. PCI is somewhat uncommon nowadays, let alone ISA, although PCI-capable motherboards are still easy enough to find, including new.) – Stephen Kitt May 13 at 14:44
  • Okay, I might post another question then, once I get around to finding out details. – Tomas By May 13 at 14:49
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    We need to know what the card is. You may not be able to get drivers for it even if you can connect it. Many modern machines can't run DOS, and systems like DOSBox and QEMU can't access ISA hardware directly either. – user May 13 at 15:26
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There's basically two possibilities you may find:

  1. The ISA card is a fairly trivial piece of hardware, using I/O ports or memory-mapping only. In this case, it is pretty likely an USB-to-ISA or PCI-to-ISA adapter will work. It is, however, also pretty likely a modern PCI-express or USB replacement is cheaper, thus rendering the adapter useless.
  2. The ISA card is not-so-trivial, might use DMA or even take over the bus completely, as many of the more complicated co-processor cards do. I happen to have a Motorola 68040 card on an ISA slot that does take over the bus completely and talks to the graphics card and disk controllers directly - something like that would be worthy of spending quite some of money for an adapter card - I don't, however, know of any adapter card that would support such a setup.

The above, either too simple to justify the cost of an adapter card, or too complicated that it is really working, is probably the main reason such ISA adapters are no longer available in the market.

Your best possible options are either buying a relatively modern used PC that still has ISA slots (they're still available on eBay, if you're lucky, you'll find a very small and relatively recent Pentium board like they were used for PoS systems, that's what I did), or investing in a more modern setup, you can still buy new ISA-PC setups targetted at the embedded market (at a price, however).

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    The problem with a lot of relatively recent (in the last 10 years or so) PC motherboards with ISA support don't support ISA DMA, since it can't be implemented using a PCI to ISA bridge without additional connections that PC chipsets don't support anymore. ISA DMA can be supported with LPC to ISA bridges though. I'm not sure how well bus mastering works with either kind of bridge. – Ross Ridge May 15 at 18:09
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As mentioned is a comment above by @scruss, some manufacturers (such as ARS Technologies) have created a USB device that provides an USB-ISA bridge and an ISA slot.

ARS tech usb2isa card

It is an expensive option, as it's a niche product, and most people needing this kind of item will be in a position where they have to support some old mission-critical peripheral that can't easily be replaced.

This approach deals with the hardware issue, but you may also have issues finding drivers to support your old ISA card in a modern OS. One person has recorded their experience of getting an old ISA network card working here.

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