Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!sun-barr!newstop!texsun!texbell!uhnix1!sugar!ficc!peter
From: peter@ficc.uu.net (Peter da Silva)
Newsgroups: comp.unix.wizards
Subject: Re: What kinds of things would you want in the GNU OS?
Message-ID: <4357@ficc.uu.net>
Date: 31 May 89 13:35:54 GMT
References: <106326@sun.Eng.Sun.COM> <4315@ficc.uu.net> <338@arc.UUCP> <8587@chinet.chi.il.us>
Organization: Xenix Support
Lines: 20

In article <8587@chinet.chi.il.us>, les@chinet.chi.il.us (Leslie Mikesell) writes:
> Besides the obvious intent of the name, there is the advantage for
> database usage that some directory operations are atomic.  That is,
> you will normally never be able to access a filename in an inconsistent
> state.  You cannot say the same for the contents of the files unless
> explicit locking is done.

I've been thinking about this statement, but it still does not make any sense.
If you do a read or write that does not span block boundaries it should be
atomic. So a binary read or write that's a power of two bytes in length should
have no problem. Certainly I don't think I've ever seen a problem with utmp.

Or with directories, for that matter... which after all are just files with
16-byte records in them (except for on BSD, and I think they still don't
cross block boundaries).
-- 
Peter da Silva, Xenix Support, Ferranti International Controls Corporation.

Business: uunet.uu.net!ficc!peter, peter@ficc.uu.net, +1 713 274 5180.
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