Mailing-List: contact cygwin-help@cygwin.com; run by ezmlm List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-owner@cygwin.com Mail-Followup-To: cygwin@cygwin.com Delivered-To: mailing list cygwin@cygwin.com From: ericblake@comcast.net (Eric Blake) To: antiskid56-cygwin@yahoo.com, cygwin@cygwin.com Cc: "James R. Phillips" Subject: Re: Is tar -cjf deterministic? Date: Mon, 12 Sep 2005 19:27:22 +0000 Message-Id: <091220051927.4057.4325D69A000797B000000FD922007613940A050E040D0C079D0A@comcast.net> > I've noticed more than once that when I recreate a bzip2'ed tar archive on > cygwin, the file length is slightly different. Yet it expands into the same > directory tree (as determined by recursive diff). > > Is there something nondeterministic about tar and bzip2 on cygwin? If so, is > it unique to cygwin? Not unique to cygwin - file timestamps are preserved in tar, and when the timestamps change, the compression dictionary changes, hence leading to different compression ratios. -- Eric Blake volunteer cygwin tar maintainer -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/