IBM PC hacking

[Tony Duell]

> Later, they switched to one row of 64K DRAMs soldered in, with sockets for
> another three rows.  Some (all?) of those motherboards could be trivially
> modified to take 2 rows of 64K plus two rows of 256K.

I can't rememebr if the PC 64K to 256K board has the socket for the extra 
address mux chip, etc, but I think it doesn't.

All IBM PC/XT boards that I've seen can be modified to take 2 rows of 
256K chips. And on all the boards I've seen, all 4 rows of RAM are 
socketed, so it's easy to replace rows 0 and 1 with said 256K chips. Then 
just plug in the 'S158 (or 'F158), solder the jumper and go.

-tony