Date: Sun, 18 Oct 2009 09:28:29 -0400 From: Jerry McAllister <jerrymc@msu.edu> To: Tim Judd <tajudd@gmail.com> Cc: freebsd-questions@freebsd.org, Stevan Tiefert <stevan-tiefert@kabelmail.de> Subject: Re: small question about tape-based dumps Message-ID: <20091018132829.GB68596@gizmo.acns.msu.edu> In-Reply-To: <ade45ae90910171909kd29a19ep560c6b65fbe0e22@mail.gmail.com> References: <1255727601.4640.4.camel@x1-6-00-11-09-00-e4-00.search.b.superkabel.de> <20091016213732.GA61433@gizmo.acns.msu.edu> <ade45ae90910161943o7695d436wed8b8a69d92ef994@mail.gmail.com> <20091017232131.GB66093@gizmo.acns.msu.edu> <ade45ae90910171749g5accf984j9e5d766193fb9d39@mail.gmail.com> <1255828485.5100.3.camel@x1-6-00-11-09-00-e4-00.search.b.superkabel.de> <ade45ae90910171909kd29a19ep560c6b65fbe0e22@mail.gmail.com>
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On Sat, Oct 17, 2009 at 08:09:22PM -0600, Tim Judd wrote: > On 10/17/09, Stevan Tiefert <stevan-tiefert@kabelmail.de> wrote: > > Am Samstag, den 17.10.2009, 18:49 -0600 schrieb Tim Judd: > >> On 10/17/09, Jerry McAllister <jerrymc@msu.edu> wrote: > >> <snip> > >> > >> > You do not need to. dump alrady writes that when it finishes each time. > >> > If you to that, you will get a second one at that location. > >> > > >> > You do not need to do the rewind and mt fsf between each dump. I just > >> > do it to make it very clear to myself in my scripts what I am expecting > >> > and that I am doing it right. > >> > > >> > ////jerry > >> > >> <snip> > >> > >> If dump is the tool for tapes, and tar is named after tape archives... > > > > Please, no flamewar!!! > > Wasn't planning on starting one. Sorry if it came across that way. > > > > >> Do both of these utilities write the *proper* EOF to whatever medium > >> it's writing to? > > > > They both write EOF. > > > >> I bring this up, because dump can also write to a file on a formatted > >> FS. Does the file end with this same EOF? What does tar do? > > > > There is only one EOF: The EOF. > > > > > >> Why have a mt weof function if it's useless? I'm loosing the logic in > >> this one, trying to make sure things work as they should. I admit > >> tapes on bsd are so foreign to me, I might as well be speaking > >> $another-language. > > > > weof is not useless. There are some file operations without writing an > > EOF, like streams or something like that, but tar and dump are writing > > with an EOF at the end of files :-) > > > So it's a item for "good measure" rather than an item "as necessity" > in creating backups. Not a good measure. It would do something different from what you expect. You might get 2 EOF-s in a row and the system think you have two files - one with stuff and one empty one. ////jerry > > Thanks for all the info. I'm happy knowing more. > > > --Tim > _______________________________________________ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to "freebsd-questions-unsubscribe@freebsd.org"
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