Messages in this thread | | | Date | Sat, 25 May 2002 11:08:30 +0200 | From | Robert Schwebel <> | Subject | Re: patent on O_ATOMICLOOKUP [Re: [PATCH] loopable tmpfs (2.4.17)] |
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On Fri, May 24, 2002 at 08:25:38PM -0700, Linus Torvalds wrote: > With RTLinux, you have to split the app up into the "hard realtime" part > (which ends up being in kernel space) and the "rest". > > Which is, in my opinion, the only sane way to handle hard realtime. No > confusion about priority inversions, no crap. Clear borders between what > is "has to happen _now_" and "this can do with the regular soft realtime".
... which in turn results in the situation that applications must be implemented as kernel modules.
> Your claim was that RTLinux made realtime hard to do with licensing > concerns. MY claim is that if you actually were to use RTLinux, you > wouldn't _have_ any licensing concerns: the kernel module would have to > be GPL (both because the kernel wants it that way _and_ because you get > the liences to the patent that way), and the user-level code that uses > whatever data the RT module produces is no longer hard realtime at all.
This is only correct for open-loop applications. Most real life apps are closed-loop.
Robert -- +--------------------------------------------------------+ | Dipl.-Ing. Robert Schwebel | http://www.pengutronix.de | | Pengutronix - Linux Solutions for Science and Industry | | Braunschweiger Str. 79, 31134 Hildesheim, Germany | | Phone: +49-5121-28619-0 | Fax: +49-5121-28619-4 | +--------------------------------------------------------+ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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