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From: conklin@kaleida.com (J.T. Conklin)
Newsgroups: comp.os.386bsd.development
Subject: Re: any chance of...
Date: 30 Mar 93 10:26:17
Organization: Kaleida Labs, Inc., Mountain View, CA
Lines: 34
Message-ID: <CONKLIN.93Mar30102617@ngai.kaleida.com>
References: <matthew.733339478@femto.engr.mun.ca> <1p84lbINN1j1@iskut.ucs.ubc.ca>
<JKH.93Mar30023319@whisker.lotus.ie>
<1993Mar30.041706.28158@coe.montana.edu> <C4p2x6.7s7@agora.rain.com>
Reply-To: conklin@kaleida.com
NNTP-Posting-Host: ngai.kaleida.com
In-reply-to: rgrimes@agora.rain.com's message of Tue, 30 Mar 1993 09:12:41 GMT
Rodney> Humm got a question, does tar handle files with link counts > 1, or
Rodney> does it dump the file x times, if it does the latter this is a BAD
Rodney> idea. As a lot of the man pages are hardlinked.
Cpio stores the link count and inode # and dumps the file x for each
instance of a linked file. This allows you to start extracting an
archive "from the middle" and have all the files be extracted
correctly. This is not a big concern for us, since the dists are
unlikely to be extracted in that manner.
Tar stores a linkflag and a linkname, and only dumps the first copy.
But tar has a fixed record size, so part of the last 512 byte block
contains junk. This makes the archive larger --- moreso if the
remainder of the block isn't zeroed (I don't know if GNU tar does
this).
When you don't have linked files, cpio archives are smaller. But if
you do, the advantage of not storing the 512/2 bytes quickly eaten up.
For example, a binary distribution of pbmplus is a 20M cpio file, and
a 6M tar file.
Afio, a cpio work-alike, has an option that only stores the first
instance of a multiply linked file. Every version of cpio I've
encountered is able to extract these files. Perhaps we should use
afio to generate the dists.
--jtc
--
J.T. Conklin <jtc@wimsey.com> | Your source for floppy distributions
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