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From: Florian Weimer <Weimer@CERT.Uni-Stuttgart.DE>
Newsgroups: comp.lang.ada
Subject: Re: gnat: time-slicing
Date: Tue, 16 Jul 2002 17:18:40 +0200
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lutz@iks-jena.de (Lutz Donnerhacke) writes:

> First you need a OS able to perform a task switch while performing
> system IO.  Most multitasking OS do not do this. While performing a
> system call, this call can not interrupted by normal tasking.

Threading libraries (maybe except GNU Pth) for such systems usually
change all I/O system calls (in fact, section 2 libc routines) into
non-blocking callls, so that they can schedule during I/O.