What did it use for expansion slots? I've seen pictures of the motherboard, but can't really identify what goes where. I don't see any 8-bit ISA slots (which makes sense, as it has a 16-bit bus), and I don't see 16-bit ISA slots (which makes sense because IBM didn't invent that standard until a year later! Also 16-bit ISA would have too many address lines for this thing.)