You know, I've always kept my eye open for P4 boards with ISA slots BECAUSE THEY ARE COOL.
Never did find one cheap enough for me to justify forking over the cash for my own use.
In hind-sight, considering the almost nil load of ISA parts in more modern gear, a P3 Tualatin board will get the job done just fine and they are WAY WAY cheaper.
Such boards exist because in factories, refineries and industrial machines there are custom made proprietary ISA add-in cards that would require designing a PCI card (and the associated software/drivers) from scratch to replace -and to which- the company that created the original card may not even be around anymore. (Creating Copyright and Patent issues.) Such an endeavor could easily cost a company 10's of thousands of dollars and that it was a huge problem when ISA first went away. Spending a few $100 for a motherboard was a quick-fix and a stop-gap measure while they (the equipment users) waited for whatever industry (the equipment suppliers) to come out with upgrade parts that did not require ISA.
A few years ago I worked on some proprietary Pentium 1 boards that had custom proprietary interface circuitry built right on the board and to which no one ever made an add-in card to replace.
These were used in fuel transfer stations at refineries and such. They controlled all the pumps and valves and so forth which had controllers that required the custom interface.
Changing the motherboard would have required a custom add-in card, new software and (if using good sense) replacing all the pump and valve controllers to industry standard parts.
Replacing one of those motherboards was in the range of $5000-$6000 from the manufacturer (who only had refurbed boards BTW) so they were quite willing to pay me a bunch to fix them.
I still keep my eyes out for good deals on ISA-P4 boards, but not for me anymore. I would flip them to someone else.
Very nice that the one you found has mostly solid polymer caps.
I may get one - just cause I'm geek and they are COOL.
GRUMPY OLD FART - On Hiatus, sort'a
Mann-Made Global Warming. - We should be more concerned about the Intellectual Climate.
You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.