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Cake day: July 26th, 2023

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  • Been ages since I had to recompile a Linux kernel to deal with hard real time (via RTAI) but I recall emc2 being a great alternative to all the fussing around recompiling as some one did all the work for that.

    I also recall using this resource . Eventually I just made a class for the threads I was using to wrap POSIX and RTAI calls for periodic tasks and chose which was the underlying method on a compiler flag. If I was on my desktop I could proof of concept most things in POSIX and then test on the RTAI machine. If I need to revisit this again I may dust off my old class and add freeRTOS stuff to it so I can prototype on Linux then try to squeeze it on to an esp32.








  • chuck@lemmy.catoxkcd@lemmy.worldxkcd #2867: DateTime
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    11 months ago

    Ah I’ve gotten to the point where I have to define what “frame” and epoch each time base is in before I’ll touch the representation of time( Unix,Gregorian, etc) .To be honest I’m probably just scratching the surface of time problem.

    Hell probably the reason we haven’t seen time travellers is we suck at tracking time and you probably need to accurately know your time and place to a very good precision to travel to a given point and we can’t say where and when that is with enough accuracy to facilitate where to land. And people don’t want to land in the earth’s surface or 10000 km away from a stable orbit. Maybe some writer can build that out for a time travel book or to discount it for some reason lol




  • Huh what do you propose then, go back to the 1960s and ensure they are only using VOR and DME ground equipment. There isn’t a check sum to check on GPS/GNSS it just a bunch of satellites broadcasting what they think is the correct time. If you jam those and replace them with signals close enough but wrong values you can trick the math that’s used inside the GPS/GNSS receiver that computes the the position (and velocity), and it looks like this signal can be introduced slow enough to trick the receiver in real-world applications. One trick to protect yourself is to ensure the signals you receive are from the direction you expect but we aren’t going to attach directional antennas on every face of a civilian aircraft, to ensure the strongest signal is from the top of the plane and not the bottom. Essentially civil navigation equipment isn’t supposed to be messed with and if it is authorities are supposed to go over and arrest and fine the idiots doing things over the radio they shouldnt. When the bad guy is a government well yea I guess that plan doesn’t work and governing bodies such as ICAO should impose penalties like no commerical aircraft from companies from those countries are not allowed elsewhere.





  • Well it’s dark humor and I can see how some are deeply offended. The post even says it’s a slow growing treatable form, so personally I’ll laugh at the joke. It’s not like he’s end stage untreatable form of cancer. Like you know arch linux running on WSL level cancer.