As much as I hate writing "getter" functions for referencing global variables, I would when I knew I didn't have the right address yet. Write them first to error out loudly, then when you have the actual addresses replace the error out code.
How to avoid a BSOD on your 2B dollar spacecraft
81–90 of 160 posts
Re: How to avoid a BSOD on your 2B dollar spacecraft
#82One must have balls of steel to run windows on a spaceship.
Well, if your account is only a Home Edition, you will not get the same support as if you upgrade to Universal Galactic Edition which has a LTS measured in generations.
Also, if you want RDP then I think you need to upgrade to Universal Galactic Edition
Re: How to avoid a BSOD on your 2B dollar spacecraft
#83Earlier quoted context omitted.
Having discussed this same question with the more experienced members of my team, the only conclusion I can draw is that the customer (US Government) is incredibly risk averse. Any unexpected entry into safemode would require a report, multiple meetings with the customer, and them being pretty angry. Their line of reasoning seems to be "Safemode->Something is wrong->Why is something wrong? We're not paying you to be…
> Any unexpected entry into safemode would require a report, multiple meetings with the customer, and them being pretty angry. Their line of reasoning seems to be "Safemode->Something is wrong->Why is something wrong? We're not paying you to be wrong". I'm personally of the opinion that safemode isn't that bad. It's fully recoverable and shows the system is working properly. To the last part first: Good that safe mod…
There are faults IDs that trip if certain telemetry goes outside of a normal range. If a safemode were to occur, we would investigate which faults tripped and at what time, and use those to construct a "story" of what happened on the satellite before it entered safemode. We're also constantly recording every telemetry that comes down, so we could reference any telemetry we wanted as far back as months in the past.
To your point, yes you're correct. The cause of the safemode is much more interesting than the fact we entered it.
Re: How to avoid a BSOD on your 2B dollar spacecraft
#84Thee 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…
I worked on UAVs in the late 00s and early 10s and it was all VxWorks as well. We were playing around with some embedded Linux but it wasn't used on anything "serious," despite some of our dreams.
Re: How to avoid a BSOD on your 2B dollar spacecraft
#85Author 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,…
FSW development is done by a different team than mine but I believe it's just managed through gitlab. Releases are done through tags, and any updates that need to be made have tickets created for them and are developed by the FSW team. Final approval is given by certified product engineers and then a new tag is created for that release.
Like I said this is a different team but from what I've seen the process is fairly modern given how old our hardware is. I'm not sure of the exact process of how it's loaded onto the satellite through.
Re: How to avoid a BSOD on your 2B dollar spacecraft
#86Thee 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…
Seconding the vxWorks and bare metal. Never seen Windows or Linux on a satellite bus. Haven't really touched payloads but I've seen some wonky things shipped to orbit by universities and not all them have been cubesat student projects.
I've used Linux on the payload processor computer of a spacecraft so I know it happens :P
I've also worked with a payload running Windows Embedded.
Re: How to avoid a BSOD on your 2B dollar spacecraft
#87Re: How to avoid a BSOD on your 2B dollar spacecraft
#88I would bet the schedule didn't allow much time to doing subsystem level test with on-board computer, so everyone went to the big test praying for the best.
That or inexperienced programmers were involved, assuming they were not scared of modifying memory addresses directly.
As for the safe-mode, if it happened maybe you could say you were randomly injecting errors in the memory during runtime and spacecraft entered safe mode as expected, would not be far off from the truth, just do not mention it was unintended :)
Re: How to avoid a BSOD on your 2B dollar spacecraft
#89Why is it using memory-mapped stuff in the first place rather than some sort of messaging system that would allow more defensive programming?
If I were to guess -- At the lowest level, that's what the hardware does. I wouldn't be surprised if they have a library to wrap that with something more friendly, but something has to translate that into writes to memory-mapped addresses, and whatever that is was configured with the wrong addresses...