Re: RTAI/RtLinux

From: Erwin Rol (erwin@muffin.org)
Date: Sat May 25 2002 - 11:30:29 EST


On Sat, 2002-05-25 at 18:05, Larry McVoy wrote:
> On Sat, May 25, 2002 at 11:05:32AM +0200, Erwin Rol wrote:
> > Both Linus and Larry seem to be not very interested in hard-realtime
> > Linux additions, this is OK.
>
> I'm interested in hard realtime. I'm extremely uninterested in changes
> to the mainline source base in order to get them. That's exactly why
> I like the RT/Linux approach so much, it is the least invasive to the
> kernel and - surprise - also has the best performance.
>

If you take a look at RTAI's history you will see that RTAI has been
using a HAL and a very small kernel patch long before RTLinux started
using that.

> If people were to learn that real time and multi-user throughput are
> by definition mutually exclusive, I'd be a lot happier. As it is,
> we have the SGI/Montevista crowd cramming their stuff into the kernel
> and each "little" thing makes the kernel a less pleasant place to be
> and brings it one step closer to the point when it gets abandoned
> like ever other OS in the history of our field.
>
> > Also apparently there is the idea that all RTAI developers want to
> > become rich by getting the patent out of the way and sell RTAI.
>
> So the thing I have a problem with is that Victor says that all GPL
> is fine. You say you are all GPL. So far, no problem. Yet you keep
> coming back and saying there is a problem, that Linux is going to
> be out of the running as a real time platform because of the patent.
> I don't get it, why should the patent prevent Linux from being used?
> All it does is say "if you aren't making money, we aren't making money,
> if you are making money, we want a cut". That seems OK to me, in fact,
> it seems more than OK. It seems like someone who is trying to help
> those who are helping others and charge those who are charging others.
> That's smart, that's good. It means that FSMlabs will be here 20 years
> from now, still supporting this stuff, whereas all the "we'll survive
> off of support" people will have long since gone under.

It is not so OK if you keep in mind that this "if you make money, we
want a part of it" is backed by a questionable patent. And if FSMLAbs
still will be there in 20 years is not something you or I can predict,
they might be bought by some large embedded firm tomorrow and the patent
with it, and as far as i understand the patent license this means it is
void when that happens.

- Erwin
 

> --
> ---
> Larry McVoy lm at bitmover.com http://www.bitmover.com/lm



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