OT the spirit of Spirit

[erik hansen]

--- Mark Wieder <mwieder at ahsoftware.net> wrote:

> My favorite story concerning the Mars projects
> involves Wind River's
> OS and debugging. NASA has a policy of "test
> what you fly and fly what
> you test", which involves, among other things,
> leaving your debugging
> code in place. There's a lesson to be learned
> here:
> 
>
http://www.kohala.com/start/papers.others/pathfinder.html
> 
> "VxWorks contains a C language interpreter
> intended to allow
> developers to type in C expressions and
> functions to be executed on
> the fly during system debugging. The JPL
> engineers fortuitously
> decided to launch the spacecraft with this
> feature still enabled. By
> coding convention, the initialization parameter
> for the mutex in
> question (and those for two others which could
> have caused the same
> problem) were stored in global variables, whose
> addresses were in
> symbol tables also included in the launch
> software, and available to
> the C interpreter. A short C program was
> uploaded to the spacecraft,
> which when interpreted, changed the values of
> these variables from
> FALSE to TRUE. No more system resets occurred."

using the Message Box will never be the same!

Erik

=====
erik at erikhansen.org    http://www.erikhansen.org

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