I’m trying to find the computer with the hugest uptime. So far the Voyager space probes are the best I can find (44 years) but I bet there’s some mainframe out there that has been chugging-along since before 1977.

@requiem looked into VMS systems? ive heard reports of them having uptime in the decades, and getting part of their datacentre destroyed and still surviving. maybe a few of them are kicking about still?

@eris thats what got me on this path, but I haven’t found any specific examples.

@requiem I don't know that either one of the Voyager probes has an _uptime_ that long; that's how long they've been in unattended operation, but I'm pretty sure they've both been restarted multiple times, both for software updates and upgrades while they were performing their primary missions and due to subsequent failures as their systems degrade. For example, Voyager 2 was patched due to a correction of a flipped bit in 2010, and I recall from the stories at the time that it rebooted.

SunOS machine was up for over 6 years here:

For major uptime, you need a system with no power outages, and either no updates or some clever rebootless update.

@elb @requiem

@elb someone else mentioned this, but I haven’t been able to confirm it.

The software on them is updated with some frequency, and on of them stopped responding for awhile, but their computers are redundant as far as I have seen there has been no downtime where the the both parts of the control computer have gone offline.

That said if you have info please share 😁


I don't know about another computer having run through the reset; I do understand that the Voyager spacecraft have twin computers, but I don't _think_ they're redundant. I think they ran different software. As I understand it, this is one of the things that let them improve compression between Saturn and Uranus.

It's quite possible that there is a control module that is different from those computers, however. I'd buy that science and control are different.

@requiem "The CCS and FDS were designed separately because of the input/output rates required by the FDS, even if computationally they could have easily been integrated together. The Voyager probes would be the last probes built by JPL to keep these functions separate, however."

@requiem A lot of good information here, although it's not clear exactly what a CCS load entails:

@elb “Voyager employs three dual-redundant computer systems per spacecraft.”

Lotta cool info in that book, wish I could find a print edition.

@requiem it says dual redundant, but didn't say how updates are handled, and explicitly says the science module is two independent computers running different software and the attitude module never has both running at the same time.

There's probably more info somewhere.

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