In article ,
Jim Logajan wrote:

It's been a while since I worked on any RTOS, but I seem to (probably
incorrectly) recall that applications running on VxWorks (the OS used on
the Mars Explorer, among other spacecraft) generally have full run of the
memory. That is, there is no distinction between the app and the OS as far
as access privileges to memory or I/O.

There are versions of VxWorks that are certifiable to DO-178B level A.
Kind of hard to do that while allowing full run of the memory.


And I'll admit it eventually doesn't matter how reliable the OS is once it
passes a certain reasonable level, since the application(s) are always
going to be less reliable.

um, not always. the complexity of the OS could dominate the complexity
of the app, especially if the OS provides protection for the app (e.g.,
partitioning).

--
Bob Noel
Looking for a sig the
lawyers will hate