back to the AGC, was Re: TTL 7400's Available - test-drb@ccmp.vtda.org

4 Jan 2007

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Subject: Re: back to the AGC, was Re: TTL 7400's Available
   From: Brent Hilpert <hilpert at cs.ubc.ca>
   Date: Thu, 04 Jan 2007 01:29:50 -0800
     To: General at priv-edmwaa05.telusplanet.net,
 "Discussion at priv-edmwaa05.telusplanet.net":On-Topic and Off-Topic Posts
 <cctalk at classiccmp.org>

Allison wrote:

  (And it
confirmed that the AGC was constructed from a single gate/IC type.)  
 That statement I believe is in error.  While the logic used was RTL and a
 single family type the logic elements for that family by the mid 60s were
 more diverse than just a two input NOR. My junkbox contains parts from 
There are now two, perhaps three, sources from the period that indicate it was
a single gate/IC type: a dual 3-input NOR in 10-pin flat-pak. Read the
document Chuck ref'ed above (although there do seem to be some
mis-rememberings in there such as LCD instead of EL displays). I'm well aware
of the state of RTL/IC development at the time, but high-reliabiliy design
doesn't necessarily correlate with whats current in the rest of the industry.
Keep in mind the design started years before 1967/8. The IC spec sheets are
dated 1965. 
Around early '66 a friend that whose father worked for Grumman and NASA 
gave me several of the 10 pin flat packs with info.  They were indeed 
3input NOR but, he also provided a RS-FF in the same package.  They sat 
in my collection for years until they were lost in a move.

Shortly after that a neighbor that worked for Airborne and he brought me
an engineering junk box that contained fairchild uL9xx parts galore plus
a lot of aerospace qualified transistors.  It was then I started 
working on understanding logic and how useful those RTL parts were.

As to displays LEDs were indeed available in the mid 60s though they 
were not bright and the only color was red.  I also have Burroughs
Nixies from then and a 40 character selfscan from the era.  I'd never
seen EL used in anything other than backlight. There was also VF (vacuum
florescent) displays as they were easily driven with available transistors.
One of the problems then with transistors was low (usually less than 60V)
breakdown voltage and most common devices were more like 25V.  That 
complicates drivers for HV displays. Though for a price there were a 
lot of things available than were new or low volume.

Allison