[Milsurplus] Logic Modules by DEC

[ED SHARPE]

 Ulrich Do you still have any of your PDP=8  systems?
The PDP-8 (first model - from 1965)  we have  at SMECC has  those  same type discrete  logic  flip chips also.we are  blessed  with  serial number  18.we  have an 8S  also  in  storage that  I would  like  to see out i the  display area. 
The  PDP 8s was a  serial buss machine  and had a cycle  time  of  20 microseconds  compared  to the full  first  model  which  was 1.5 microseconds. The  8s  I have been told  had the teletype interface in  an external back plane  so if  I  want it to talk  it  will have to  be  found or  a substitute made  for it

Dec put   the  computer at  an affordable  price 1965   was  $20,000 alot of money  but cheaper than the competition at the  time and versatile  for lab work.
Ed Sharpe Archivist for SMECC
In a message dated 5/7/2020 2:19:04 AM US Mountain Standard Time, milsurplus at mailman.qth.net writes:

G'day all,
discussing these ready-made "universal" logic modules I'd like to add some additional information as I was an active users of these many years ago:
The leader in this area at the time was DEC (Digital Equipment Corporation) which made a large array of such modules - called "Flip-Chip" - which were not only used in their own computers (e.g. PDP-8 in various flavours then) but supplied to third parties for e.g. process control, machine tool control and automation. They provided a way for automation suppliers to design their system without having to resort to printed circuit manufacturing or electronic design on the component level. DEC supplied backplanes with wrap pins and the system would be designed and wire-wrapped by the automation supplier. It also meant that prototyping was fast and modification to the wiring easy. Efficient was also field repair replacing modules. Often there was no software/computer in the system, just hardwired logic.
As you may see from the handbook below, modules using discrete logic and modules using integrated circuits were offered at the same time. Not all automatione etc customers would switch to ICs immediately as it would have meant a redesign of their system.
If you'd like to have a look at the DEC offering in 1968 there is a good copüy of the "Digital Logic Handbook 1968" on bitsavers.org here (kindly note it is a large PDF file):www.bitsavers.org/pdf/dec/handbooks/Digital_Logic_Handbook_1968.pdf
Back in 1978 I started my own "personal computing" system (I needed to learn as I am a telecomms engineer and had no experience in process computing) with an old PDP-8/S which runs on R-modules (discrete) and I built my own terminal and printer interfaces using mostly R-modules on a DEC backplane as described above. Later I moved to PDP-8/L and PDP-8/I which both use M-modules (7400 TTL logic). The 8/S came out in 1966 and the 8/I in 1968. 
Have fun with your hobby abd stay safe!
Ulrichhb9aik - vk2ani8044 Zurich/Switzerland
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