Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!tut.cis.ohio-state.edu!pt.cs.cmu.edu!b.gp.cs.cmu.edu!Ralf.Brown@B.GP.CS.CMU.EDU
From: Ralf.Brown@B.GP.CS.CMU.EDU
Newsgroups: comp.sys.ibm.pc
Subject: Re: .1 archive format?
Message-ID: <25d015ae@ralf>
Date: 7 Feb 90 11:33:50 GMT
Sender: ralf@b.gp.cs.cmu.edu
Organization: Carnegie Mellon University School of Computer Science
Lines: 28
In-Reply-To: <1990Feb6.185751.14120@agate.berkeley.edu>

In article <1990Feb6.185751.14120@agate.berkeley.edu>, laba-1ee@e260-4g.berkeley.edu (Gary H. Aochi) wrote:
}Does anyone know what the following format means?
}
}EMACS15E.ARC.2
}             ^
}
}I know of arc, zip, tar, unix compress (Z), but what is that number?
}Other files are of the form *.# or *.ARC.#
}What is this?

You can just ignore the .2.  This is a "generation number" which (usually)
indicates the number of times a file has been created.	The first time an
"EMACS15E.ARC" is created in a particular directory, it becomes *.1; the second
time, it becomes *.2, and so on.  I said "usually", because the generation
number can be explicitly set.  The PC-BLUE collection on SIMTEL20 uses
generation numbers of 1 and 2 to distinguish between ASCII and binary files.

What use is a generation number, you say?  Well, if you tell the OS to allow
multiple simultaneous generations, you can keep multiple versions of the same
file around.

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"How to Prove It" by Dana Angluin              Disclaimer? I claimed something?
14. proof by importance:
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