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How to avoid a BSOD on your 2B dollar spacecraft

clarkwakeland.com

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Re: How to avoid a BSOD on your 2B dollar spacecraft

#111
post #70

Thee are a bunch of comments here asking why one would run Windows on a spacecraft. I am a spacecraft engineer. I don’t see anything in the linked article indicating that they are actually running Windows - the BSOD claim is tongue-in-cheek, or at least that’s how I read it. I also don’t know of anyone anywhere that runs Windows on a spacecraft, with the exception of laptops used by astronauts. Typically one runs vxW…

Indeed, and it’s clearly stated in the article: > Safemode is the satellite equivalent of a blue screen of death. It’s about avoiding safemode, and more generally about the end-to-end QA/testing process for satellites before they’re sent up into orbit. It’s very clearly not about actual Windows BSODs, it’s just written in a tongue-in-cheek style. Those commenting about “wtf windows on a spacecraft” clearly didn’t rea…

>> customers have to be informed of every incident where a satellite flips into safemode in TESTING!

Because the customers are almost certainly running their own metrics, tracking failure rates over time. An increasing rate of failures across a program is probably a sign of something going wrong at a higher level. Remember too that there is "testing" and testing. One is you playing around with the software at your workstation, the other is the more formal testing as monitored by the acceptance and standards people.

Re: How to avoid a BSOD on your 2B dollar spacecraft

#112

Thee are a bunch of comments here asking why one would run Windows on a spacecraft. I am a spacecraft engineer. I don’t see anything in the linked article indicating that they are actually running Windows - the BSOD claim is tongue-in-cheek, or at least that’s how I read it. I also don’t know of anyone anywhere that runs Windows on a spacecraft, with the exception of laptops used by astronauts. Typically one runs vxW…

So could this finally be the year of Linux on the Moon? ;-)

Which OS do the Mars rovers run?

Re: How to avoid a BSOD on your 2B dollar spacecraft

#114

Why is it using memory-mapped stuff in the first place rather than some sort of messaging system that would allow more defensive programming?

To the shock and horror of many programming-inclined people, it turns out that having "arbitrary memory read/write" commands on a remote computer that *must* keep the mission going is quite useful. I can tell you a little first-hand account of where this helped a satellite formation flight mission I worked on. The communication system was working fine in terms of signal strength, but many command packets were ignored…

It occurs to me that writing software for spacecraft could demand an entirely different paradigm than writing software for traditional applications.

For example, you could use an OS that is deterministic down to the last detail, and have a "digital twin" / virtual machine of the spacecraft computer here on Earth, kept in sync with all sensor and actuator activity out in space. Before issuing any command to the spacecraft, you branch the digital twin, issue the command on the branch, and make sure everything looks good.

With this method, you wouldn't even need to read memory locations on the spacecraft, you could just read them on the digital twin. Then test the memory patch on the digital twin and make very sure that it won't brick your spacecraft before you transmit it.

Re: How to avoid a BSOD on your 2B dollar spacecraft

#116
post #97

Earlier quoted context omitted.

And apparently the astronaut !touchscreen! GUI is written in Javascript (not a joke).

I think I was the person who originally proposed to implement the crew control UI in a web browser, and I participated in a week-long retreat in beautiful Bend, Oregon where we implemented the first prototype. At the time, some very good flight software engineers had been working diligently on a new UI framework that was written in the same code style and process as the rest of our flight software. However, I noticed…

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Re: How to avoid a BSOD on your 2B dollar spacecraft

#117

Author here: I should clarify the satellite is not running Windows. Instead, it’s running its own custom OS written in C called Flight Software (FSW) specifically designed for the satellite onboard computer. Re-reading the post, I see how the title, my analogies, and poor attempts at humor would give the incorrect description of what’s happening with the satellite when it enters safemode. I’ll amend the post soon. Th…

Can you speak at all as to how the development on this software is done? Is it distributed with centralized version control? Does release and engineering process interact with the version control at all? Are there mechanisms that link defect reports, corrections, and sign offs back to version control and into the build system? I got lost recently in how the Shuttle software was managed, mostly through IBM mainframes,…

> I got lost recently in how the Shuttle software was managed, mostly through IBM mainframes, and z/OSs facilities for all the above. I'm curious how modern development looks in comparison.

Do you have any references for this? I also recently went down a research rabbit hole of the history of computing on Earth and in space - super interesting stuff. And the parallels are quite obvious when you look at it.

Re: How to avoid a BSOD on your 2B dollar spacecraft

#118
post #97

Earlier quoted context omitted.

And apparently the astronaut !touchscreen! GUI is written in Javascript (not a joke).

I think I was the person who originally proposed to implement the crew control UI in a web browser, and I participated in a week-long retreat in beautiful Bend, Oregon where we implemented the first prototype. At the time, some very good flight software engineers had been working diligently on a new UI framework that was written in the same code style and process as the rest of our flight software. However, I noticed…

So the implementation speed came solely from developer experience and not someone pushing away this custom UI framework implementation aside?

Re: How to avoid a BSOD on your 2B dollar spacecraft

#119
post #96
post #92

Earlier quoted context omitted.

> And apparently the astronaut !touchscreen! GUI is written in Javascript (not a joke). why would that be mistaken for a joke?

Because they don't want people confusing the launch pad with left-pad and having the spaceship slowing down because of Facebook Like button embeds.

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