RE: [ECOS] How to debug synchronisation in the usbs.c in a new usb-driver for the ARM at91sam7s...

["Robert Bryce" <rob at mobilia-os dot com>]

Hi Nick,

> If I had my way, mutexes and condition variables would be the only
> synchronization primitives available in the OS.

Hm.  I will agree that one set of primitives is all that an OS needs to
provide.  Keeps the model simpler.  I'm really indifferent on which set,
though I do prefer semaphores.  In the end, it's just not a big deal.

> In general, the OS on its own is not real time, only an entire system,
> OS+application, can be described as real time. [...]
> A real time OS cannot make non-real time code become real time.

Yes!  Conversely, though, an (otherwise) real-time app isn't without a
real-time OS.

I did some work with hierarchical scheduling that could support both
real-time and non-real-time app's simultaneously - concerns are similar to
your example (IP stack) - inter-process dependencies.  There's been some
interesting work in hybrid schedulers too.

Thanks for the discussions.  Interesting.

--Rob


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