Re: Wait-free Synchronization, RTLinux and CSP

[A E Lawrence <A.E.Lawrence@xxxxxxxxxxx>]

Lawrence Dickson wrote:

> I did mention RTLinux a few months (?) back. It is actually not Linux,
> but an all-powerful and very small embedded environment over which 
> Linux runs as the lowest priority process. This is done with a clever
> adaptation of the Linux macros CLI and STI. Linux communicates with
> embedded "masters" through pipes which behave much like channels. I 
> think it is a natural both for development of a super-DOS and of a
> CSP-based superstructure including occam - with complete mastery of
> the machine at the same time as all the tools of Linux are available.


It was your post that I remembered, I think.


RTLinux seems to be out of favour with the majority of the Linux 
community over a patent issue and openness.

Most of the current work is on RTAI

http://server.aero.polimi.it/projects/rtai/

which uses a similar approach, indeed forked off RTLinux.

At first sight, RTLinux is not obviously CSP friendly in that its 
communication model is non-blocking and based on shared memory objects.
But that is associated with  wait-free synchronisation which I think is 
 inherently buffered, at least for the "universal" objects. I don't 
think there is any problem in describing them as suitable CSP processes, 
but I
have been trying to understand the various papers where the ideas are 
introduced. They seem to lack simple examples which does not help.

The only books that seem to mention the ideas are Attiya & Welch and Lynch.


Adrian