24 Apr
2008
24 Apr
'08
7:32 p.m.
On Apr 24, 2008, at 11:45 AM, Jules Richardson wrote:
You know, I had a thought - I wonder if those 64K
boards can't be
jumpered beyond the 256KB boundary? Maybe that's why I'm remembering
a 256KB limit on the original machines (and using original IBM
expansion boards). Getting around that would mean physically hacking
the address lines / decoding of the boards...
They can. Both my 5150s are of the 16-64KB mainboard variety. The
configuration switches on this board are not documented for memory
configurations over 256 KB, but in practice follow the convention for
the later 64-256KB mainboard. In this way I have configured my
machines at times up to 320KB, using a full complement of 64KB on the
motherboard plus one Tekram multifunction card with 256KB installed.
I believe conventional wisdom has the limit for this board at 576KB,
but I have not confirmed it experimentally.
ok
bear