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Re: [Bug-tar] High per file overhead?
From: |
Joerg Schilling |
Subject: |
Re: [Bug-tar] High per file overhead? |
Date: |
Sun, 26 Feb 2006 13:21:35 +0100 |
User-agent: |
nail 11.2 8/15/04 |
Phillip Susi <address@hidden> wrote:
> > As cpio does not offer a -H newc format, let me asume that you are talking
> >
> > about the -c or -H crc format...
> >
>
> Yes, it does have a newc format, see the info page. It is also the
> format used by the linux kernel for initramfs images.
A quick look into the cpio source
http://cvs.opensolaris.org/source/xref/on/usr/src/cmd/cpio/cpio.c#1216
verifies that there is no such format in cpio.
Maybe you are not talking about cpio but about one of many cpio clones.....
> > du only counts the file contend and a part of the meta data (not counting
> > e.g.
> > the "inode" - see: /usr/include/sys/fs/ufs_inode.h)
> >
>
> Right, but the timestamps, owner, and mode only take up a handful of
> bytes, which cpio also stores.
The cpio archive format -Hcrc never has become a standard and the POSIX cpio
format
has been declared obsolete 5 years ago because it it not extensible.
Less useful formats may have less overhead but this is an inferior argument
if you have to decide for a portable and extensible format. The POSIX cpio
format is e.g. limited to 8 GB files and the SVr4 crc format is limiet to even
less.
If you like to have an archive format that completely fits your actual needs,
you will end up wit > 100 incompatible archive formats.
> > If you compress the result, the remaining difference is less than 1%.
>
> I'd say archiving my Maildir is a rather real world use, so this is
> somewhat relevant. I did notice though, that once compressed, the
> difference in size is greatly diminished.
See above.
Jörg
--
EMail:address@hidden (home) Jörg Schilling D-13353 Berlin
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