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In space, no one can hear you kernel panic (2020)

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Re: In space, no one can hear you kernel panic (2020)

#11

Post by baud147258 »

somat wrote: post #10

"From the dawn of the Space Age through the present, NASA has relied on resilient software running on redundant hardware to make up for physical defects, wear and tear, sudden failures, or even the effects of cosmic rays on equipment." An interesting case study in this domain is to compare the Saturn V Launch Vehicle Digital Computer with the Apollo Guidance Computer Now the LVDC, that was a real flight computer, tri…

> Worse is better?

Maybe if you know what the tradeoffs are and are ready to deal with the deficiencies (by rebooting fast). And didn't they had issues with the lunar module Guidance Computer on the first moon landing?

Re: In space, no one can hear you kernel panic (2020)

#12

Post by phanarch »

rogerrogerr wrote: post #6
throwaradfy5745 wrote: post #5

How would these considerations affect Musk's space cloud ?

Starlink very likely leans toward “many cheaper satellites that may fail” instead of “fewer expensive satellites that are less likely to fail” Their advantage in the satellite-internet industry is that they can launch stuff fast and cheap; very likely this drives different tradeoff decisions than the regime this article talks about.

The Starlink tangent misses something important about why software reliability in satellite systems is categorically different from hardware reliability.

Re: In space, no one can hear you kernel panic (2020)

#13

Post by throwup238 »

somat wrote: post #10

"From the dawn of the Space Age through the present, NASA has relied on resilient software running on redundant hardware to make up for physical defects, wear and tear, sudden failures, or even the effects of cosmic rays on equipment." An interesting case study in this domain is to compare the Saturn V Launch Vehicle Digital Computer with the Apollo Guidance Computer Now the LVDC, that was a real flight computer, tri…

> There is a lesson to be learned here but I am not sure what it is.

Restart your Claude Code sessions as often as possible

Re: In space, no one can hear you kernel panic (2020)

#15

Post by KurSix »

somat wrote: post #10

"From the dawn of the Space Age through the present, NASA has relied on resilient software running on redundant hardware to make up for physical defects, wear and tear, sudden failures, or even the effects of cosmic rays on equipment." An interesting case study in this domain is to compare the Saturn V Launch Vehicle Digital Computer with the Apollo Guidance Computer Now the LVDC, that was a real flight computer, tri…

I think the lesson is that redundancy can exist at different layers

Re: In space, no one can hear you kernel panic (2020)

#16

Post by dfox »

> running identical software on multiple computer systems is the name of the software-architecture game

In the railway signalling industry (which for historically obvious reasons is obsessed with reliability) there even is a pattern of running different software implementing the same specification, written by different team, running on a different RTOS and different CPU architecture.

Re: In space, no one can hear you kernel panic (2020)

#19

Post by wongarsu »

KurSix wrote: post #14

The contrast with modern software development is striking. Today we often rely on fast iteration and patching problems in production. Spacecraft software is the opposite

On the other hand a lot of SpaceX's success can be attributed to applying modern software development methodology on spacecraft. They are very much doing agile development, betting on velocity enabling fast iteration.

That has lead to some of the best rockets ever developed, and the largest satellite constellation by far. But part of the secret sauce is creating situations where you can take risks. Traditionally anything space-related deals in one-offs or tiny production volumes, so any risk is expensive. A lot of SpaceX's strategy is about changing this, whether that's by testing in flight phases the customer doesn't care about, being their own best customer to have lower-risk flights, or building constellations so big that certain failure scenarios aren't a big issue (while other scenarios still have to be treated as high-risk high-impact)

Re: In space, no one can hear you kernel panic (2020)

#20

Post by superxpro12 »

dfox wrote: post #16

> running identical software on multiple computer systems is the name of the software-architecture game In the railway signalling industry (which for historically obvious reasons is obsessed with reliability) there even is a pattern of running different software implementing the same specification, written by different team, running on a different RTOS and different CPU architecture.

This is also true of the space shuttle. The failover '5th' processor was running an implementation done by a completely different sandboxed team to hedge against institutional or systemic errors not caught by the first team. So much thought put into these systems.

This, in the context of 'modern vehicle safety standards' still makes me cringe when considering the "safety" put into modern autonomous vehicle systems.

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