Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!cs.utexas.edu!execu!sequoia!rpp386!jfh From: jfh@rpp386.Dallas.TX.US (John F. Haugh II) Newsgroups: comp.unix.wizards Subject: Re: What kinds of things would you want in the GNU OS? Summary: Looks like mandatory file locking ... Message-ID: <16607@rpp386.Dallas.TX.US> Date: 1 Jun 89 02:28:13 GMT References: <106326@sun.Eng.Sun.COM> <4315@ficc.uu.net> <338@arc.UUCP> <8587@chinet.chi.il.us> <4357@ficc.uu.net> Reply-To: jfh@rpp386.cactus.org (John F. Haugh II) Organization: River Parishes Programming, Plano TX Lines: 19 In article <4357@ficc.uu.net> peter@ficc.uu.net (Peter da Silva) writes: >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). One very important difference. namei() returns a pointer to a LOCKED inode. The modification to the directory is very atomic, whereas the modification to a regular file is not. The file is not locked automagically as is the case with directories. -- John F. Haugh II +-Button of the Week Club:------------- VoiceNet: (512) 832-8832 Data: -8835 | "AIX is a three letter word, InterNet: jfh@rpp386.Cactus.Org | and it's BLUE." UucpNet : !bigtex!rpp386!jfh +--------------------------------------