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From: davidsen@steinmetz.steinmetz.UUCP (William E. Davidsen Jr)
Newsgroups: comp.sys.ibm.pc
Subject: Re: ARC/ZOO/TAR
Message-ID: <8042@steinmetz.steinmetz.UUCP>
Date: Tue, 1-Dec-87 12:53:19 EST
Article-I.D.: steinmet.8042
Posted: Tue Dec  1 12:53:19 1987
Date-Received: Fri, 4-Dec-87 22:29:54 EST
References: <3027@umn-cs.cs.umn.edu>
Reply-To: davidsen@crdos1.UUCP (bill davidsen)
Distribution: na
Organization: General Electric CRD, Schenectady, NY
Lines: 49

In article <3027@umn-cs.cs.umn.edu> amit@umn-cs.UUCP (Neta Amit) writes:
| ... discussion of zoo and arc ...
| This weekend, a public domain TAR (courtesy John Gilmore) has been posted
| on comp.sources.unix, and is now implemented under Unix and MS-DOS. It
| is likely to be ported to VMS, MAC, Amiga.
| 
| PDTAR offers a number of significant advantages over both ZOO and ARC:
|   - It is the de-facto standard in the Unix world. Info-exchange with
|     Unix machines is much easier with TAR.
The quantity of discussion in std.unix would make me think that's not
decided yet. Isn't cpio in posix?

|   - It creates the structure it needs
Somewhat. I lost eight hours this weekend redumping stuff on one machine
and loading to another. The first time I used tar, the second cpio. tar
was faster, and small (it handles links at dump rather than load time).
tar doesn't save directories, as you said it creates them. You lose all
info about owner, permissions, time modified, etc. It also *doesn't
create empty directories!!* Many programs which keep status and restart
info in directories will leave the directories empty when shut down.

|   - It is fast; on the small sample that I did -- faster than ARC or ZOO
|   - It can compress, and the resulting archive is small; on the sample above, 
|     smaller than the .arc or .zoo files
The "standard" tar doesn't compress, at least on V7, SysIII, SysV, or
Ultrix. What you are proposing is (yet) another file format entirely.
This is not a bad thing, but somewhat negates your earlier argument
about standard. A regular (uncompressed) tar file will more widely
readable than the compressed format.

---
I'm not saying that your idea is without merit, and it should be
considered as another alternative format. However, the question is not
as clear as you believe. The advantage of archivers is that they allow
easy random access to the files in an archive. The price of this is
compressing them separately, which reduces the compression and increases
the cpu needed. They allow easy replacement of individual files in the
archive.

I will be evaluating pdtar in the next few weeks, and I expect it to be
useful, and reliable (J.G. does good stuff). I don't expect it to be the
only archiver I use, on UNIX, on PCs, and most of all on (yecch) VMS. At
the moment zoo is the only thing I have which runs in all environments.

Please post all reasonable discussion, mail flames to me directly.
-- 
	bill davidsen		(wedu@ge-crd.arpa)
  {uunet | philabs | seismo}!steinmetz!crdos1!davidsen
"Stupidity, like virtue, is its own reward" -me