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Nasa are currently working to fix a computer error aboard Voyager 1. The probe's computer system runs at around 8000 instructions per second and has about 68kB of memory. Due to the interplanetary distances involved, even at light speed it takes 45 hours to send a signal and get a response. When asked about the unique challenges this poses, an engineer said "that's actually about average for a modern CI system".
@andrewt Modern CI systems must have been sneakily unleashed on the unsuspecting public by NASA just so as to train zillions of engineers in the unique challenges of debugging faraway space probes!
@andrewt They are talking about the delays ? 
#FBPE @andrewt Yup. Minutes to change the software, a couple of days to get it though the build system.
@andrewt NASA has it easy, they have a local replica of Voyager 1, so at least they can test changes locally in an equivalent environment.
@xavier
There are no functional replicas of the voyager spacecraft on earth. No hardware simulators.
Afaik, there is only the Development Test Model/Proof Test Model which are nonfunctional and hanging in auditoriums/museums (and at this point, mostly composed of dummy elements, eg. one of them had the main spacecraft bus stollen for development of another probe).
@xavier I've even heard form various accounts that the voyager spacecraft *predate* the practice of keeping hardware replicas around for simple space probes.
@developing_agent oh, that's news to me, thanks for letting me know!
@andrewt reminds me of Jenkins alright...
@andrewt this is the most true thing anyone has posted
@andrewt Are you sure Voyager 1 hasn't been backdoored by the latest liblzma update?
@andrewt So you’re saying a vi session is out?
@andrewt I didn’t realise the old boy was still running. My parents were teenagers when Voyager flew past Titan.
@ProfesseurRenard Yes! It's had a few glitches and a few bits have had to be turned off because the battery is dying, but this space probe is older than me and still going. I mean it's sending back gibberish at the moment because some of its memory is corrupted, but apparently they're pretty confident they can fix it because somehow they're still sending out software updates. And here I am with a decade old laptop that might have to just be replaced 
@andrewt What's a "CI system"
@alextecplayz @zarky @andrewt a tool for programmers to write questionable code and pass that code to a complex verification process until some of it sneaks past the testing and validation apparatus to become the next release. Bugs in the release are found by users who throw error reports into a customer support apparatus designed to make them give up before finishing. Any bugs that make it through that process are used to update the CI system so similar bugs are caught in the future.
@zarky @andrewt Continuous integration system.
Something you use in software development to, among other things, report back to you whether your change breaks parts of the software you did not intent to change.
Often CI systems do build all the source code (not just changed code) and run a lot of tests so the turn around times can be quite high. Having to wait an hour or more until your change set is built on CI and test results are ready is not uncommon.
@andrewt
NASA paid for it, but it's JPL doing all the work…
Managed by Caltech, JPL is NASA’s only federally-funded research and development center.
