I'm thinking about boosting the RAM of a Tandy 1000 HX without adding a DMA board. (There's one on eBay right now... The seller is asking $69 for it, and I don't even know if it is fully populated.) I think I could piggyback some static RAM chips on top of the ROM, and then route the appropriate read/write signals to those chips. I would have to do some address decoding too. If it works, it would be darn cheap. And the computer would at last become usable. However, I wonder if the BIOS would see the extra memory. How does it know/determine how much memory is installed in the computer?