Curt Wuollet

Hi Scott

Absolutely, there are several free and probably a few commercial realtime extensions sets for Linux. I won't go into a lot of technical detail here but there is a lot af activity and information is fairly easy to come by.

The original one is RTLinux which is a hard Realtime scheduler that runs under the Linux kernel with "normal" linux as a lower priority task . Then there's KURT from Kansas University which is intended as soft realtime for eg. multimedia and such. There is also RTAI from Italy which, I guess, requires less special programming. There are the POSIX RT extensions which will eventually become part of the normal kernel. I know I'm still missing one or more free systems. Zentropix was doing RT and were
gobbled by, I believe Lineo, and then there's Hard Hat Linux from Monte Vista? Since the Linux embedded market is extremely hot these days, announcements are coming just about every day.
What they will do in terms of performance is highly subjective and hardware dependent, but the people who are doing this stuff are very serious and are using Linux for a reason. One good resource is and a search on google for real time linux will kill an afternoon chasing links.

I have no doubt that, if and when we need true real time performance, finding a package that meets our needs will be easy enough . Getting agreement on which one will be more problematic :^) I'm sure some of the other list members have looked at one or more packages in great detail and even used them for control. I have been interested, but don't have a project that needs RT yet.


Curt Wuollet

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Daniel Krippner

At the moment I am porting a SoftPLC to Linux - I am a student working for 3S (see sig). I am using RTAI right now, and there is a good chance I will take a close look at RTLinux in the not too far future...
I am not a very good programmer yet, a experienced guy may have solved my task in a few days, but if you need somebody's help with the step to hrt, I would offer my expertise :)-) - the much there is of it...
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