On Mon, Jan 14, 2002 at 05:44:38PM -0500, Wayne babbled thus:
> Date: Mon, 14 Jan 2002 17:44:38 -0500
> From: Wayne <[EMAIL PROTECTED]>
> Reply-To: [EMAIL PROTECTED]
> X-Mailer: Mozilla 4.75 [en] (WinNT; U)
> To: PinkFreud <[EMAIL PROTECTED]>
> CC: [EMAIL PROTECTED]
> Subject: tar and rpm
>
>
> Actually, *.tgz stands for tar-gnu-zip. It runs gnu-zip on the tar file. the
> result is a compressed tar file. 'tar' stands for Tape Archive. It's an old
> format (possibly from the 70's), well burned in, and obviously still very much
Actually, I was comparing .tgz and .tar.gz - they're identical, but
.tgz is a DOS-friendly extension, also typically used for Slackware
packages nowadays.
> in use. tar's original
> intended use was to stream archive files to tape in a way that retains all
> the attribute information (mod times, permissions, etc) about the file and
> it's original place in the directory heirarchy. 'cpio' (similar function) is not
> so popular these days
> but I am not sure why. Tar does a great job of retaining all the file info
> so when you explode it you have what you thought you had. It also has
> some other useful intelligence. After experimenting with many, tar is
> my archiving program of choice (the choice for many others too, I take it) .
>
> Comparing tar amd rpm are like apples and oranges. Let's be careful mixing them.
If you really want to get technical, RPM is a modified cpio, and can be
fairly easily converted back to cpio format, as rpm just uses a
stripped set of cpio headers.
And, to further confuse the issue, I seem to recall that Debian's .deb
packages are just a modified ar archive. None of the packaging formats
in common use today (.rpm, .deb, .tgz) are original - they're simply
based on existing archive formats.
>
> tar is ONLY a program to put a directory structure into a single file
> while maintaining all the attributes of those files as well as their place
> in the tree. *.rpm's, on the other hand, are package files with much
> packaging info. This means: dependency info, version info (of the
> package, not the files), where the files should be placed for the
> program to run, what their permissions should be (something thought out
Not to get picky, but tarballs also store permissions. :)
> seriously during packaging), and other info related to "packaging".
>
> Converting from one to the other could only be a hack job with information
> certainly
> lost in the process. They are different formats, with different intentions, for
> different
> purposes, designed in different decades by different generations with different
> mentalities.
> (boy that was a mouthfull. it's true though.)
The biggest issue is dependencies. Personally, I've always found them
to be annoying to work with, as upgrading a single package can often
trigger warnings that affect most of the rest of a distribution.
Fortunately, such warning and errors can be suppressed, if you know
what you're doing, but not everyone does - which makes upgrading a
general PITA once one descends into dependency hell.
>
> The fact that tar is used for software to be installed speaks of it's
> reliability and the fact
> that it accurately retains everything about the individual files and the
> directory structures it encodes. It can collect source code, libraries, make
> files with compile and linking instructions, configuration scripts and scripts
> coded to throw files out to various places in your directoriess and script code
> to reset permissions... but it is NOT a packaging format. A packaging format
> (rpm) is a very different animal.
See above. I should mention that Slackware's package utilities also
look for a script inside .tgz files - while it's not necessary for it
to be present, if it is found, it will be run automatically upon
installation of the files within the package (make no mistake -
Slackware .tgz packages ARE packages, as well as .rpm and .deb).
>
> Redhat as put so much into their packaging format and made it so robust that
> many distro's now use it. That's at tribute to Redhat. I gather there is a lot
> to the 'rpm' format. A lot of intelligence in it.
RPM is fairly robust. Unfortunately, this can lead to troubles
sometimes, like the dependency hell described above. .tgz packages are
more basic, but if one understands what's required (or knows how to
find out what's required - ldd works wonders), it can be far less
painful to upgrade.
Of course, this depends on personal preference, much as the old
'Which distribution is best?' argument. I also recommend sticking with
the packaging format your chosen distribution uses - it makes life much
simpler in the end.
*snip*
> Wayne
--
Mike Edwards
Brainbench certified Master Linux Administrator
http://www.brainbench.com/transcript.jsp?pid=158188
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