15 Jun
2003
15 Jun
'03
7:55 a.m.
I see you have higher standards than IBM, for a while
after the AT was
released they sold ram that was two chips piggy backed so they could get more
ram on the board.
Hmm.. The oriignal PC/AT motherboard did have piggybacked RAMs, but it
wasn't an IBM kludge. Those were special RAM chips (the pinouts were
strange, with pin 1 actually used for something and the CAS/ signal from
each chip brought out separately (I think it was CAS/)), and I don't
think they were soldered together (looks more like ultrasonic welding to
me). I'd assumed these were a 'standard' 128K RAM module, something like
a Mostek part I once saw (18 pin DIL) which was a ceramic module with 2
chips soldered on top.
Incidentally, I have seen piggybacked sockets in the catalogues. 16 pin
ones with all pins commomed except 4 and 15 (RAS/ and CAS/ for normal
DRAMs IIRC) and 28 pin ones with all pins commoned except 20 (CS/ for a
JEDEC SRAM or EPROM). Interesting idea...
-tony