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/
This archive was generated by hypermail 2b29 : Fri May 31 2002 - 22:00:15 EST