4 ms·

c++ is not considered safe for any RTOS system, in fact you won't find it used in Aviation embedded devices (referring to the big 3 ) Tools yes, you can higher

by throwme_1980 10y ago

c++ is not considered safe for any RTOS system, in fact you won't find it used in Aviation embedded devices (referring to the big 3 ) Tools yes, you can higher level languages to your heart's content.

vonmoltke 10y ago
Huh? The F-22A, F-35, P-8, and P-3 are all flying C++ code. Those are just the programs I have personally touched (not necessarily the code, though). Where did you get the idea that it "is not considered safe for any [real-time] system"?
- jordanb 10y ago
  The F-22 avionics are mostly Ada. F-35 is mostly C++ though. If you want a good face-palm go read up on the "decision-makers" advocating making the switch. I saw a quote by a general blaming the F-22's cost overruns on the "Ada Operating System". But don't worry, C++ is a "COTS Industry Standard" so you can bet there were no overruns on the F-35. /s
  - pjmlp 10y ago
    The cost of the F-35 program shows how good that decision has been.
  - vonmoltke 10y ago
    > The F-22 avionics are mostly Ada. Yes, including the piece I directly touched. It was deemed to minor to be worth the cost of rewriting.. Hell, when I left the program we still had an arthritic VAX to build on, should we ever need to rebuild the code. As for your last line, see my comment elsewhere about blaming the carpenters instead of the tools. :-)
- unboxed_type 10y ago
  As far as I understand all vehicles you mentioned are not subject to DO-178 regulation. If they were then C++ code would have been much less likely be used. It is because C++ code is much more difficult to prove correct either using 100% test case coverege (DO-178B) or thru formal methods (DO-178C). Please correct me if I am wrong, I am doing a research on a similar topic.
  - planteen 10y ago
    The F-35 (JSF) is DO-178B. The RTOS itself (INTEGRITY) is mostly C and C++. http://www.militaryaerospace.com/articles/2013/10/software-code-f-35.html http://www.militaryaerospace.com/articles/2013/10/software-c...
    - unboxed_type 10y ago
      Well the article says that F-35 runs operating system compliant with DO-178B, right. But it does not say that control logic software (applied software) was a subject to DO-178B certifcation. Anyone can buy a license for DO-178B RTOS, it is not very expensive actually. But to certify your own control avionics algorithms is a whole different story. Agree?
      - planteen 10y ago
        I agree development of the avionics is different from the RTOS. But what makes you say that the avionics algorithms aren't DO-178B? That is something the customer (gov't) would specify to the contractor. I didn't ever work on the JSF avionics code to know the development process. Did you? A lack of press releases about it does not mean it is not DO-178B compliant. Reading the JSF coding standard, it sounds like all libraries must be DO-178B: "All libraries used must be DO-178B level A certifiable or written in house and developed using the same software development processes required for all other safety-critical software. This includes both the run-time library functions as well as the C/C++ standard library functions. [10,11] Note that we expect certifiable versions of the C++ standard libraries to be available at some point in the future. These certifiable libraries would be allowed under this rule. "
        unboxed_type 10y ago
        Good point. As far as I know there are no DO-178B complient C++ libraries available yet (STL, for example). If you know any please point out. My reasoning is as follows: While civil avionics must comply with regulatory safety standards, military avionics is not. So economically speaking there is a little sense for them to do such costly certification just to ensure quality.
planteen 10y ago
What? The most popular choice for aircraft RTOS seems to be INTEGRITY which is written C/C++ itself. http://www.militaryaerospace.com/articles/2013/10/software-code-f-35.html http://www.militaryaerospace.com/articles/2013/10/software-c...

vonmoltke 10y ago

Huh? The F-22A, F-35, P-8, and P-3 are all flying C++ code. Those are just the programs I have personally touched (not necessarily the code, though). Where did you get the idea that it "is not considered safe for any [real-time] system"?

jordanb 10y ago
The F-22 avionics are mostly Ada. F-35 is mostly C++ though. If you want a good face-palm go read up on the "decision-makers" advocating making the switch. I saw a quote by a general blaming the F-22's cost overruns on the "Ada Operating System". But don't worry, C++ is a "COTS Industry Standard" so you can bet there were no overruns on the F-35. /s
- pjmlp 10y ago
  The cost of the F-35 program shows how good that decision has been.
- vonmoltke 10y ago
  > The F-22 avionics are mostly Ada. Yes, including the piece I directly touched. It was deemed to minor to be worth the cost of rewriting.. Hell, when I left the program we still had an arthritic VAX to build on, should we ever need to rebuild the code. As for your last line, see my comment elsewhere about blaming the carpenters instead of the tools. :-)
unboxed_type 10y ago
As far as I understand all vehicles you mentioned are not subject to DO-178 regulation. If they were then C++ code would have been much less likely be used. It is because C++ code is much more difficult to prove correct either using 100% test case coverege (DO-178B) or thru formal methods (DO-178C). Please correct me if I am wrong, I am doing a research on a similar topic.
- planteen 10y ago
  The F-35 (JSF) is DO-178B. The RTOS itself (INTEGRITY) is mostly C and C++. http://www.militaryaerospace.com/articles/2013/10/software-code-f-35.html http://www.militaryaerospace.com/articles/2013/10/software-c...
  - unboxed_type 10y ago
    Well the article says that F-35 runs operating system compliant with DO-178B, right. But it does not say that control logic software (applied software) was a subject to DO-178B certifcation. Anyone can buy a license for DO-178B RTOS, it is not very expensive actually. But to certify your own control avionics algorithms is a whole different story. Agree?
    - planteen 10y ago
      I agree development of the avionics is different from the RTOS. But what makes you say that the avionics algorithms aren't DO-178B? That is something the customer (gov't) would specify to the contractor. I didn't ever work on the JSF avionics code to know the development process. Did you? A lack of press releases about it does not mean it is not DO-178B compliant. Reading the JSF coding standard, it sounds like all libraries must be DO-178B: "All libraries used must be DO-178B level A certifiable or written in house and developed using the same software development processes required for all other safety-critical software. This includes both the run-time library functions as well as the C/C++ standard library functions. [10,11] Note that we expect certifiable versions of the C++ standard libraries to be available at some point in the future. These certifiable libraries would be allowed under this rule. "
      - unboxed_type 10y ago
        Good point. As far as I know there are no DO-178B complient C++ libraries available yet (STL, for example). If you know any please point out. My reasoning is as follows: While civil avionics must comply with regulatory safety standards, military avionics is not. So economically speaking there is a little sense for them to do such costly certification just to ensure quality.

planteen 10y ago

What? The most popular choice for aircraft RTOS seems to be INTEGRITY which is written C/C++ itself. http://www.militaryaerospace.com/articles/2013/10/software-code-f-35.html http://www.militaryaerospace.com/articles/2013/10/software-c...