sbradford26

25 ms·

241.
by sbradford26 8y ago
A couple different ways to avoid the issue: 1: Size the type used to store the value so that it cannot overflow even in corner cases such as a plane being on for several months. Ex. going from a 32 bit int to a 64 bit. 2: Have a flag that y
242.
by sbradford26 8y ago
In the case of aircraft though a company could find a bug and do their best to fix it quickly. But if the plan is already flying any changes to the software require a re-certification of the software which can take months.
243.
by sbradford26 8y ago
The code would most like still be counted but that software would probably be either DAL D or DAL E. Here is a the wiki for the standard that software has to meet for commercial aircraft. It explain the DAL (Design Assurance Level) levels a
244.
by sbradford26 8y ago
Most likely there is not much that you can look at but this overview of the space shuttle can give you a lot of insight into how software and hardware are designed for flight critical applications. I believe this was posted a while ago here
245.
by sbradford26 8y ago
Well in this you get into a circular argument, because if you did include Linux then you would need to verify every line of code that is being used. Which is why you would never use linux and why it wouldn't be included. *This is in re
246.
by sbradford26 8y ago
If you know what you are doing it is not difficult, but if you are doing it for the first time it a good tool to learn how to think about all the repercussions of how you program something. MISRA isn't really to catch problems with c i
247.
by sbradford26 8y ago
My favorite recommendation to people. Take a C or C++ program they have written and compile it with full MISRA. Definitely makes things more interesting.
248.
by sbradford26 8y ago
That seems much more reasonable to me. Mostly because planes are rebooted for maintenance every so often between flights and customers(Airlines) would be not be okay with a 1 hour reboot time. There are also usually maintenance tests that c
249.
by sbradford26 8y ago
So this lines of code estimate are spread across all the systems on the aircraft. One reason for all of the lines is that everything is done in C. Then really the more exact reason is that every command on an aircraft is monitored. You have
250.
by sbradford26 8y ago
So that depends on if you mean a power source temporarily goes down or if a box experiences a power blip. So in the first case each box usually has 3 different sources of power, something like the generators on the engines, then backup on t
251.
by sbradford26 8y ago
So on a project like this, you do not use many standard libraries. It is usually explicitly stated that you can't use anything from the std c library and such. Also source lines of code are usually calculated as lines of code that need
252.
by sbradford26 8y ago
"One interesting fact is that the FAA claim that it will take about one hour to reboot the GCUs - so there clearly isn't a reset button." I am incredibly surprised by this, most higher level flight control systems have power
253.
by sbradford26 8y ago
Usually the hardware is tri or even quad redundant so the system can handle one of the boxes halting execution while it is either reset or other action is taken. If several failures happen one box may be powered off by the others to stop er
254.
by sbradford26 8y ago
I think part of what is argued is that people need to look at their software and determine what failure modes are not acceptable. It is impossible to design a system that won't fail so the focus should be on designing parts that detect
255.
by sbradford26 8y ago
So windows 10 has added openssh. I am not sure if it has left beta but it definitely is a step in the right direction. https://www.howtogeek.com/336775/how-to-enable-and-use-windo...
256.
by sbradford26 8y ago
I would say that is because in the US only the people most into biking use their bikes to commute. They have to want to bike enough to put up with no bike lanes and such. This attracts people who want to ride fast, there is also very little
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by sbradford26 8y ago
Geothermal definitely helps overall efficiency. Sadly the upfront cost is still pretty high. Also solar helps in other ways because it makes it so less heat is absorbed into the roof of the house.
258.
by sbradford26 8y ago
Yes a heat pump for heating is very efficient when the outside temperature is above a certain temperature(aka there is heat to pump). But running a heat pump as an air conditioner is not nearly as efficient. In the case of heating any losse