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From: sef@kithrup.COM (Sean Eric Fagan)
Newsgroups: comp.unix.xenix.sco
Subject: Re: Xenix files..
Message-ID: <1991Jan02.055643.20677@kithrup.COM>
Date: 2 Jan 91 05:56:43 GMT
References: <1990Dec31.005602.7520@robobar.co.uk> <1990Dec31.184413.16309@bbt.se> <1991Jan1.234509.3207@robobar.co.uk>
Organization: Kithrup Enterprises, Ltd.
Lines: 26

In article <1991Jan1.234509.3207@robobar.co.uk> ronald@robobar.co.uk (Ronald S H Khoo) writes:
>Actually, I'd say that's true on Xenix as well.  Can you think of anything
>more stupid than the SCO manual sections ?  *everything* is in "S" section
>so no one knows what's a system call and what's not.

Well... what's a system call in this release won't necessarily be a system
call in the next release.  Take chsize().  In xenix, it's a system call.  In
unix (3.2, that is), it's still honored as a system call, but most people
would not be able to tell the difference if it were replaced (in the COFF
library) with a routine that only called fcntl.

Why would you want to do this?  Because it's nicer to put things in user
code (no context switching, then, which is horrible), and it might be more
efficient that way.

Note that there are also some disadvantages of that, mostly that, if your
code is buggy, you can fix a system call by mereley installing a new kernel,
while you need to compile everything that includes the routine otherwise.

Anyway, just me rambling on a bit 8-).

-- 
Sean Eric Fagan  | "I made the universe, but please don't blame me for it;
sef@kithrup.COM  |  I had a bellyache at the time."
-----------------+           -- The Turtle (Stephen King, _It_)
Any opinions expressed are my own, and generally unpopular with others.