OT - Voyager 2 is Still Alive

yep, back then we worried even about the order of every condition. You checked the most common condition first, to not waste a cycle.
 
I loved DOS. So simple I could even write it. Windows is a virus.
 
On the serious side, I was writing High Reliability software exactly at the time that Voyager software was written. My requirements were as draconian as the NASA software was. We used similar design principles to achieve this. They used a custom 18 bit computer - well 2 actually, with only 70 kilobytes RAM each - I got to use 800 kHz Zilog 8080 chips (later Z80s) with 64 Kb of RAM.

So they used a custom OS called Voyager CCS, an upgraded version of the Viking CCS. All *their* source code was written in Fortran, but I got to use assembler! -and I had to write my own OS...

This is part of why their computers/software are still running - custom radiation-hardened hardware with a very reliable OS.
 
On a sad note, the half-life on their thermal power supply is slowly fading, and in a limited number of years it will simply stop working. They have already managed to extend its life, but their number of options is running out. Somewhere between 2026 and 2032 is what some sources say they will turn off.
 
I got news for you guys milspec code was writen in machine code back then. Most likely a 4 bit processor. A lot more reliable and a lot less code over head. I know when I worked for Martin Marietta on the MX missile contract just after I was discharge from the militar every thing used 4 bit processors and machine code. Every thing was on a seiral bus as well. No windows or dos. KISS
CH
 
For my part, I wasn't speculating; The guys at JPL and BNR were tight and I got to interact with several developers during late stage development and launch.

For more details:

www.eejournal.com

Voyagers 1 and 2 Take Embedded Computers into Interstellar Space

The July issue of Scientific American magazine has a terrific review of the Voyager space mission that details the trips Voyagers 1 and 2 have made through the Solar System. The article is titled “…
www.eejournal.com www.eejournal.com
www.allaboutcircuits.com

The Brains of the Voyager Spacecraft: Command, Data, and Attitude Control Computers - News

Learn about the computers at the heart of the Voyager spacecraft operations.
www.allaboutcircuits.com www.allaboutcircuits.com
 
Dabbler said:
For my part, I wasn't speculating; The guys at JPL and BNR were tight and I got to interact with several developers during late stage development and launch.
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Fascinating what they did with basically discrete logic chips. I'm sure there is still a fairly rigorous test cycle for anything before it's uploaded. I wouldn't doubt there are some failsafes, but how would you like to be the programmer that bricked one of the Voyagers? (Or any of the remote mars/deep space missions)
 
mcostello said:
I know of a press big enough to stamp out most of a car body with one stroke. 3 stories below ground, 3 stories above ground. 1500 gallon hydraulic reservoir. Runs on Dos 1.
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Well…….

It really only goes up and down, not like it can take a wrong turn.


I was going to say not like it could get lost, but our 300ton Smetek press did in fact get lost and tried to lift the ram above the top of the press.

That blew the cylinder seals and finally the pump started sucking air and someone hit the control on the sun station nearby.

It got dark quick that night as that sub station powered 1/3 of the plant.
 
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