Re: SCO: "thread creation is about a thousand times faster than on

From: yodaiken@fsmlabs.com
Date: Sun Aug 27 2000 - 22:27:27 EST


On Sun, Aug 27, 2000 at 08:27:59PM -0700, Linus Torvalds wrote:
>
>
> On Sun, 27 Aug 2000 yodaiken@fsmlabs.com wrote:
> >
> > The beauty of POSIX 1003.13 for the RTLinux side is that we get to
> > define POSIX_SINGLE_PROCESS and forbid forbid fork and exec: making
> > threads semantics much cleaner.
>
> Well, what you think of as a "beauty" I just consider a silly cop-out by
> the standard. Basically, a lot of things can call themselves "compliant to
> the letter of the law" wrt POSIX, while still leaving the _user_ out in
> the cold.

It's silly to expect to "fork" or to "exec" via a file system in a
minimal realtime environment. These are complex activities however you
cut it. By defining a set of execution environments, the 10003.13
specification makes the _user_ confront the reality that some services
don't make sense if you are prepared to put up with only a tiny
OS overhead. POSIX 10003.13 requires you to label compliance correctly.
So, we can very clearly tell the user that running in the RT environment
gives you pthreads PSE51 and if you want PSE54 with all the features of
a full service UNIX, run in the Linux environment.

-- 
---------------------------------------------------------
Victor Yodaiken 
Finite State Machine Labs: The RTLinux Company.
 www.fsmlabs.com  www.rtlinux.com

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