5 Sep
2007
5 Sep
'07
3:30 p.m.
I wonder if there were any 80286 coprocessor plug-in
boards for the
XT before the AT?
I don't know when thay came out (relative to the AT), but 80286 add-on
boards for the XT exist(ed). There's one in my junk box. It's a
half-length ISA card containing an 80286, 80287 and glue logic, with a
ribbon cable ending in a 40 pin DIL plug that presumanly goes in the 8088
socket on the PC/XT motherboard.
I also have an 8086 board for the XT. Of course the benefit of that
processor over the 8088 was the 16 bit databus, which sould be lost if
the thing had to do 8 bit accesses to memory. So there's full 640K of
RAM on this board too. Of course it does use 8 bit transfers to access
ROMs and peripherals. This is a full-length card, again with a cable and
DIL plug to go in the 8088 socket.
-tony