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What computer and software is used by the Falcon 9? (2015)

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Re: What computer and software is used by the Falcon 9? (2015)

#31

Post by nullifidian »

mofosyne wrote: post #30
nullifidian wrote: post #15

Sounds kinda disappointing/irresponsible. Chromium is an overly complex, relatively buggy piece of software. For example I recently experienced a bug where a text I selected was significantly offset from what should have been selected given the pointer position (on linux), a misclicky kind of bug. Considering that the majority of Crew Dragon's controls are through touch screen, maybe even manual docking(not sure, but…

Unlikely that they are using javascript in the actual flight controller. Also under the screen they have a small amount of manual buttons that is likely to be seperate from the touchscreen interface logic.

>javascript in the actual flight controller.

zero chances that it's the case. I meant that in aerospace applications UI is mission critical too.

Re: What computer and software is used by the Falcon 9? (2015)

#32

Post by fdw »

davedx wrote: post #26
nullifidian wrote: post #15

Sounds kinda disappointing/irresponsible. Chromium is an overly complex, relatively buggy piece of software. For example I recently experienced a bug where a text I selected was significantly offset from what should have been selected given the pointer position (on linux), a misclicky kind of bug. Considering that the majority of Crew Dragon's controls are through touch screen, maybe even manual docking(not sure, but…

Why not Javascript? I would argue that a good usable UI in a spacecraft is a good thing, and Javascript is a great language for building UIs

> Javascript is a great language for building UIs

I disagree. It is easy to build something presentable with HTML and browsers, and there have been many JS frameworks that lower the barrier. However, that is not because JS is a good language for it; it is because JS is the only language available in that environment.

In fact, there are at least two other languages that transpile to JS, because you need JS to be able to run in a browser. But JS the language is not good enough, so you want two write your code in something else.

Building a UI in a completely different language, without a browser, is definitely harder, but you might have several advantages in the other, non-UI parts.

Re: What computer and software is used by the Falcon 9? (2015)

#33

Post by usrusr »

fsh wrote: post #11
aetherspawn wrote: post #4

Earlier quoted context omitted.

Just because they do, doesn’t mean you should. I’m running an automotive firmware project at the moment and there are such things as software integrity levels, and each time you add something to the stack you create quite a large amount of testing and validation and process that needs to be followed. And it’s pretty much impossible to take something existing like Chromium and certify it to what you need. The architec…

I believe the choice of Chromium and JS for the UI simply shows that the astronauts are merely inconvenient payloads. Gagarin's first flight was already fully automated 59 years ago.

The UI design consisting exclusively of elegant but low contrast shades of blue certainly gives a similar vibe. But that might still be misleading, perhaps they deliberately keep the routine visualizations in a low key "style over substance" passenger entertainment mode so that they have plenty of visual headroom for when something actually important combs up?

Re: What computer and software is used by the Falcon 9? (2015)

#34

Post by elteto »

A slight inaccuracy: the flight strings are not x86, but ARM, running on a custom board.

Also, only the actual graphical display application uses Chromium/JS. The rest of the system is all C++. The display code has 100% test coverage, down to validation of graphical output (for example if you have a progress bar and you set it to X% the tests verify that it is actually drawn correctly).

Re: What computer and software is used by the Falcon 9? (2015)

#35

Post by tonetheman »

ncmncm wrote: post #10

Heaven help them if the Javascript they run depends on npm components. When I read about these multiply redundant systems I always want to know what provisions are made for restarting or shutting down a part that is producing wrong answers. Can the Power device reset the machine whose instructions lost the vote? If the two cores disagree, do they both reset? Also, what is done for procedures that must not be interrup…

Why is this comment grayed out... This is so true.

Assuming they dumb enough to put chromium on a spaceship for a UI then there a good chance that yes they did use bower/npm. Unless they designed it in pure HTML/JS... again this seems unlikely ... given the blunt stupid of the initial choice.

Re: What computer and software is used by the Falcon 9? (2015)

#36

Post by elteto »

nullifidian wrote: post #15

Sounds kinda disappointing/irresponsible. Chromium is an overly complex, relatively buggy piece of software. For example I recently experienced a bug where a text I selected was significantly offset from what should have been selected given the pointer position (on linux), a misclicky kind of bug. Considering that the majority of Crew Dragon's controls are through touch screen, maybe even manual docking(not sure, but…

In this case, C++ code is written in a different style than regular applications: exceptions are not allowed, allocations are not allowed past a certain point in program initialization, raw pointers are frowned upon, etc. This is common in this type of software and when you pair it with the right development culture it really makes a difference in the robustness of the result.

Re: What computer and software is used by the Falcon 9? (2015)

#38

Post by erikbye »

SpaceX has had a booth at GDC at least two times, they attend in order to recruit game developers (programmers), as they feel these programmers work with a lot of the same constraints they do in terms of resources and experience with real-time, performant systems, etc.

Re: What computer and software is used by the Falcon 9? (2015)

#39

Post by neurostimulant »

fsh wrote: post #11
aetherspawn wrote: post #4

Earlier quoted context omitted.

Just because they do, doesn’t mean you should. I’m running an automotive firmware project at the moment and there are such things as software integrity levels, and each time you add something to the stack you create quite a large amount of testing and validation and process that needs to be followed. And it’s pretty much impossible to take something existing like Chromium and certify it to what you need. The architec…

I believe the choice of Chromium and JS for the UI simply shows that the astronauts are merely inconvenient payloads. Gagarin's first flight was already fully automated 59 years ago.

Right, I think the crew dragon is intended to fly fully automatic from launch to docking? But imagine if there is an emergency and the crew need to take over, but lo and behold, chromium crashed! Hopefully the spacecraft can still be operated without the display.

Re: What computer and software is used by the Falcon 9? (2015)

#40

Post by hoorayimhelping »

gumby wrote: post #8

Interesting that it’s three identical processors running he same software. I remember just the automated Vienna central train station used a pair of machines, x86 and SPARC, one running the logic in a procedural language (Chill) and the other running in a logic language (Prolog). They didn’t want both processors to share any code, and therefore potentially the same bug.

>They didn’t want both processors to share any code, and therefore potentially the same bug.

They're not worried about bugs, they're worried about electromagnetic radiation (which is way more present when you get outside the atmosphere) flipping bits.

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