[X] My Assistant

[hal_9000]

I want to know more about Spacecrafts' OS!
How to work a OS in a spacecraft?
What OS work in Mars Rovers?

[Guest_Richard Trigaux_*]

They do not send bad stuff in space. It has to be proven reliable. A well known operating sysem would never go in space. And a weel known "free" competitor of the previous no more. VxWorks... is it possible to buy it and install on my PC?


The languages too are an important issue. When I worked in the domain I knew that the old C was not allowed, due to memory management problems, well known from C designers who are sometimes confrontated to "unexplainable malfunctions".

As explained in the article, radioactivity too is a major problem. I remember have seen big TO3 transistors destroyed with just one ion, or a SPARC microcontroler (sun stations) sending strings of errors from radiations.

[chris]

The languages too are an important issue. When I worked in the domain I knew that the old C was not allowed, due to memory management problems, well known from C designers who are sometimes confrontated to "unexplainable malfunctions".

Richard,

The "memory management problems" in C are generally a result of badly written code. Bugs related to allocation and freeing of memory still occur, of course, but nowadays there are numerous sophisticated tools to help.

Remember that Unix systems are written in C, and are generally considered to be very secure.

Chris

[Guest_Richard Trigaux_*]

Bugs related to allocation and freeing of memory still occur, of course,

I is THIS what I was understanding with "memory management problems", and it is THIS which forbad C to be used in high reliability applications.


You may think that if people write bad code, it is not the fault of the language. Indeed it can be, if the language contains ambiguities such as signs wich effect vary depending on implicit context paradigms, or if the language does not contains built-in protections against subtle confusions by the writer. From my own experience, I know that it is very difficult to guess what is goodly written code in C. Of course there are alway people who come and tell you that your code is bad, but it seems that nobody never went with a code good enough to pass reliability tests. As for me, the only piece of flight software I ever wrote was in assembler for a small microcontroller, so it really depended only on me to have the memory properly managed, the result did not depended on mysterious functions which correct working depends on many implicit parametres.