20 Oct
1999
20 Oct
'99
3:56 a.m.
Using discrete transistors to build flop cells on that
scale would be so
large that getting the timing to work would be a real pain. Core wouldn't be
bad at all; mid 70's core technology stuffed 32K * 20 in an 8" x 4"
area with no sweat; drivers and transceivers wouldn't double that.
Ok now delete all teh integrate circuits like the sense amps and substitue
a flipchip sized module for each read amp (note some of those chips were
duals and quads). Then look at the packages of diodes and use individual
diodes.
I have trouble with the notion of the uart filling a 9
x 11 board given
that I'm holding one that's occupying 4 x 5 inches in SSI. Yeah, the shift
registers would take a bunch of space but I don't see it using anywhere
near the amount of real estate suggested.
Try a TTY PDP-8 omibus card. Keeping in mind yes the uart part of that
is only part of the card it still has tobe interfaced. The ttl only
version is a full quad card. Again as transistors it will grow.
Having had my head in the RCSRI PDP-12 and LINC-8 plus the PB-250 I have a
better idea of real machines using nothing but transistor technology.
Granted modern parts could really improve the packing density.
multilayer boards while our '60s compatriots were
laying stuff out by hand
on light tables (been there, done that, never again).
Yes, touch way to go.
I suspect you could build a pdp-8 using contemporary
layout tools and discrete
technology that, excluding the core stack, was an order of magnitude smaller.
Using '70s core technology you could get the stack somewhat smaller while
increasing the storage density by a factor of eight. The 8080 would without
a doubt be larger than the '8 and slower than the NMOS version of the chip;
it would also cost a fortune to build.
Maybe. If you cheat and use 70s core tech (ICs) that's a big savings as
the core planes were never the total system anyway. It's the
drivers/decoders that grow huge!
Also you'll never get the power/cooling of a say straight-8 even if size
reduced to come down near as fast and the ultimate problem may be cooling
or deliver the AMPs of power.
Allison