That is so bizarre, I built and tinkered with way too many machines in that era, and I only remember one combination that didn't work, two early ATAPI CDROMs on

That is so bizarre, I built and tinkered with way too many machines in that era, and I only remember one combination that didn't work, two early ATAPI CDROMs on the same chain. Everything else, just get the jumpers right and it was good to go. This was mostly in the era of ISA and then VLB "Super-I/O" cards, so maybe mobos with integrated IDE are pickier?