Patching production code

[ChrisGreaves]

Voyager 1 is sending data back to Earth for the first time in 5 months
"Since there was no way to repair the chip, the team opted to store the affected code from the chip elsewhere in the system’s memory. While they couldn’t pinpoint a location large enough to hold all of the code, they were able to divide the code into sections and store it in different spots within the flight data system."

Takes us back a ways, doesn't it?
Forty-six years, give or take.

Splitting object code into object modules, finding space in core memory, moving the modules one by one, thereby freeing up that space, and finally testing each module and working our way back up the tree.

22.5 hours there, and 22.5 hours back is akin to two-day turnaround on BHP's IBM 1401, too.

Wish I was working for that crowd ...
Cheers, Chris

[HansV]

Where did they find programmers old enough to remember how to do such things...?

[GeoffW]

I was going to say they looked on LinkedIn, but then I realised ...

[ChrisGreaves]

Where did they find programmers old enough to remember how to do such things...?

:raising hand: :screaming me! Me!! ME!!!:

[ChrisGreaves]

Where did they find programmers old enough to remember how to do such things...?

A moment's reflection suggests that they didn't have to find such programmers (which is why my phone hasn't rung).

Forty-six years ago programs were designed; they didn't leak out of fingertips on to a laptop keyboard.
Also programs were documented, including printouts of Symbol Table Cross-References, Linkage maps and all the good stuff.
Cheers, Chris

[Graeme]

Also: https://www.space.com/voyager-1-communi ... ign=MANUAL

[BobH]

That satellite is functioning with technology that is nearing 50 years old. Fifty years before it was launched, Henry Ford was still producing Model As. That it is functioning at all - in the harsh environment of interstellar space - is near miraculous.

As for finding programmers who could move the object modules around, think how little memory they have to move it around in. I find it extremely remarkable that it's sensors are still functioning after so long a time.

[ChrisGreaves]

Also: https://www.space.com/voyager-1-communi ... ign=MANUAL

We should be grateful for small mercies: "prompting its flight data subsystem (FDS) to send a full memory readout back home". I mean, just how big can that memory dump be? 1,024? Bytes? 2,048?
Cheers, Chris

[ChrisGreaves]

That satellite is functioning with technology that is nearing 50 years old.

True; a minor miracle.
Do we know what the memory is made of?
I start thinking that {t}rusty old ferrite cores are probably less vulnerable to random cosmic rays than atoms-of-whatever vacuum-sprayed onto a substrate.
Cheers, Chris

[PJ_in_FL]

Also: https://www.space.com/voyager-1-communi ... ign=MANUAL

The team in the photo looks to be the 2nd generation team.

Even so, I don't see any Gen X'ers around that table, just older coffee drinkers celebrating with boxes of donuts.

[Graeme]

Also:

https://voyager.jpl.nasa.gov/news/detai ... cle_id=127