Date: Fri, 26 May 2000 17:14:20 +0400 (MSD) From: "Aleksandr A.Babaylov" <babolo@links.ru> To: peter.jeremy@ALCATEL.COM.AU (Peter Jeremy) Cc: brian@Awfulhak.org, hackers@FreeBSD.ORG Subject: Re: file creation times ? Message-ID: <200005261314.RAA14587@aaz.links.ru> In-Reply-To: <00May26.071523est.115206@border.alcanet.com.au> from "Peter Jeremy" at "May 26, 0 07:15:22 am"
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Peter Jeremy writes: > On 2000-May-25 19:03:56 +1000, Brian Somers <brian@Awfulhak.org> wrote: > >Of course access timestamps are usually useless anyway as most (?!!) > >people will back up their system from time to time.... OOPS ! I > >never realised before now - dump *doesn't* update the access time. > > This is because dump bypasses the filesystem (it reads the underlying > device). Therefore the filesystem doesn't see the access. > > Other backup tools (tar, pax, cpio etc) access the files through the > FS amd therefore alter the access time. Some have the ability to > reset the access time afterwards - but that updates the change time, > which is probably worse. This is probably good justification for a > O_NOTACCESS (ie, this isn't a real access) flag on open(2) to request > that the access time isn't updated. I check it in FreeBSD 4.0-R open do not change atime. > In general, access time is probably the least important of the > timestamps. This is reflected in the treatment of access time > updates - unlike all other inode updates, they are not written > synchronously (non-softupdates) and don't affect soft-updates > write-ordering (so atime updates can be lost). > > As I see it, the major use of access times would be for a true > hierarchical storage manager (which transparently migrated un- > referenced files to a tape-library or similar). It's also good > for things like deleting `old' files in /tmp. See ports/18813: new port: misc/deleted this daemon uses access times [skip]......... -- @BABOLO http://links.ru/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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