21 Dec
2018
21 Dec
'18
9:30 a.m.
On 12/21/2018 09:33 AM, Noel Chiappa via cctalk wrote:
IC as in digital logic? were in production in the early 60s and RTL/DTL
the? oldest I was playing with as a kid by '66
and TTL started to appear well before 1970.? The stuff of the day was
2input Nand, Nor, 4 bit counters, and
similar SSI logic.
We forget the AGC Apollo guidance computer used a dual 3input NOR RTL
dating to 1960.? This was already
old by 1970.? People were building frequency counters with RTL
(uL914/923, MC789 and friends as
"hobbyist chips" it by then.? Least I was able to buy uL9xx, MC7XX,
MC10K,? in the late 60s for under a
dollar a package.
The transition from transistors to ICs was fast.? Cost and space were
drivers and generally speed as well.
The industry needed faster and more reliable and interconnects needed to
be fewer.? At the same time ICs
went from 1960 dual 3input nor to MSI (7483 quad full adder and 74181
ALU) in about 10 years.? The computer
industry were the early consumers.
Allison
through (I
think) the PDP-7; at least, this PDP-7 internals image
.. seems to show System Modules at the top, and FLIP CHIPs at the
bottom.
After groveling through the 'PDP-7 Maintainence Manual' (F-77A), this seems to
be accurate. In "Module Identification" (pg. 6-5), it refers to both types;
the
example on the next page uses a 4303, a 4000-Series System Module.
What's interesting is the physical layout; all System Modules at the top of
that image, and FLIP CHIPs at the bottom. No doubt this is partially for
mechanical reasons (the two used different backplanes), but I wonder about the
division into sub-systems; were the two types interspersed among each other in
individual sub-systems (rewquiring running wires from the top to the bottom),
or were sub-systems exclusively one or the other (so that the top of the bay
is one sub-system, and the bottom another)?
No doubt I could answer this by studying the prints, but time is short; perhaps
someone who worked on the one at the LCM and already knows the answer can
enlighten us!
Noel