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<== Date ==> <== Thread ==>

Subject: Re: Open source Real-time Oss / open source OS
From: Andrew Johnson <anj@aps.anl.gov>
To: EPICS Core Talk <core-talk@aps.anl.gov>
Date: Fri, 10 Jun 2005 10:45:41 -0500
NB: This is now a core-talk thread, not tech-talk...

Ralph Lange wrote:

Real time OS problems are no different than other OS problems in terms of how and why (not) EPICS is running. It's the same OSI layer that has to be implemented for a new OS.

Dalesio, Leo `Bob` wrote:

It seems that we are diverging on these. It is a little worrisome, as operating system problems are ones that are very difficult to find and fix. It would seem most efficient to limit the number of these that we employ.

This may be somewhat idealistic of me, but...

This is exactly the reason why for quite a while I have been wanting us to have an _automated_ regression test suite. There should be a whole series of tests that we can run with one command which checks out that the OSI layer for the platform it's running on does everything that iocCore expects it to do, and gives an overall pass/fail result at the end. (R3.14's libCom/test programs fail several of these requirements for a test suite.)

Someone who is porting EPICS to a new OS should just have ensure their code passes that test suite and (if we have sufficient test coverage) they can be reasonably confident that both iocCore and the CA libraries will run on the new OS. If they find a problem running EPICS on their new OS that wasn't caught by our tests, we obviously missed something in our test coverage or assumptions, and need to write another test to catch that problem.

That's the theory. In practice, once we've found a problem we tend to just fix it, and not think about it any more. I guess it's really a question of the effort involved - there's more effort and pressure to get something working than there is to ensure it won't happen again for someone else. This is why commercial companies (and probably NIF too) employ as many testers as they do, but I don't really expect we'll ever get that kind of resource level available to us.

Sorry, I guess I'm not really expecting anyone to respond to this, just forget I ever wrote it...

- Andrew
--
Podiabombastic: The tendency to shoot oneself in the foot.

Replies:
RE: Open source Real-time Oss / open source OS Jeff Hill
References:
Re: Open source Real-time Oss / open source OS Ralph Lange

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