Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!uunet!crdgw1!crdos1!davidsen
From: davidsen@crdos1.crd.ge.COM (Wm E Davidsen Jr)
Newsgroups: comp.unix.questions
Subject: Re: find
Keywords: time atime mtime ctime
Message-ID: <1917@crdos1.crd.ge.COM>
Date: 13 Dec 89 13:32:17 GMT
References: <21721@adm.BRL.MIL> <1989Dec12.060748.29698@csusac.csus.edu> <21231@mimsy.umd.edu>
Organization: GE Corp R&D Center, Schenectady NY
Lines: 24
Reply-exos:@crdgw1:To: davidsen@crdos1.crd.ge.com (bill davidsen)

In article <21231@mimsy.umd.edu> chris@mimsy.umd.edu (Chris Torek) writes:

| `ctime' can be thought of as `time of last operation that requires that
| the file be backed up'.  A backup program can decide whether a file needs
| saving by comparing the file's ctime with the time of the previous backup.

  No. ctime is the time of a change to the *inode* not the file. A smart
backup program can just save the new inode info and restore that, if
incremental dumps are being done. As an example, if you change the
access with chmod, the inode time will change, and ctime will be
updated. Since the content of the file has not changed the actual file
itself doesn't need to be backed up.

  The only backup which appears to take advantage of this is "dump," and
I'm not sure that the feature is in all versions. It is important to
understand the distinction, however, between changing the contents and
the characteristics. The field which indicates that the file content has
been changed is the modified time (find param -mtime).

-- 
bill davidsen	(davidsen@crdos1.crd.GE.COM -or- uunet!crdgw1!crdos1!davidsen)
"The world is filled with fools. They blindly follow their so-called
'reason' in the face of the church and common sense. Any fool can see
that the world is flat!" - anon