Silicone on Sapphire

[Accutron]

(03-14-2016 08:14 AM)jebem Wrote:  Is it acceptable that actually discrete 4000 CMOS series were used instead of an already commercially available SOS microprocessor to build that computer?
Yes, it is (I did it in mid 70's as well for a school project), but this is kind of speculative until someone comes up with the actual official papers showing us what was the actual technology used in that spacecraft.

Also, SOS technology was being developed at that time to be used for the military and space applications in some kind of secrecy, way before it was commercially available to the general public.
In the end what we can read in the Internet is mostly noise.

The Voyager probes had multiple computers onboard. Two of the machines were General Electric discrete TTL minicomputers with plated-wire memory, using a byte-serial architecture first built for Viking. A third minicomputer was built in discrete CMOS. These facts are thoroughly documented and not open to speculation.

It is unlikely that NASA used the CDP1802 or any other microprocessor prior to it being commercially available. They tend to use hardware that is already proven in battle. Military/space computer technology often lags behind commercial use by a decade or more, and they prefer to use ruggedized versions of old stuff. Given the development timelines of the COSMAC processors and Voyager, it's basically impossible that Voyager used a CDP1802 or anything similar.

Coming back to something mentioned earlier, the CDP1802 was definitely used aboard the STS, although not in a central processing role. It was used as a display driver IIRC. Those systems were all replaced with newer hardware in the 1990s.

Edit: Typed bit, meant byte.