[Rpm-maint] [RFC][PATCH] Large file support

Florian Festi ffesti at redhat.com
Thu Sep 10 10:53:14 UTC 2009

On 09/09/2009 08:32 PM, Ville Skyttä wrote:
> On Wednesday 09 September 2009, Florian Festi wrote:
>> Having a look at the tar formats I do not belief that switching to tar
>> is a real option. The format is just horrible (GNU tar needs over 200
>> lines to read an integer out of a header field) and full of hacks to
>> remain backward compatible (header in header + extentions). This would
>> be all not that bad if there where a nice little library we could link
>> against...
> libtar doesn't qualify?  http://www.feep.net/libtar/
> Not that I know anything about it, but it might at least satisfy "little".
It didn't look very trust worthy when visiting the page some days ago. 
Having a look at the ML archive now I am quite sure that it doesn't 
qualify. A library would need to be under active maintenance and have a 
chance to be still around in 5 or 10 years. GNU tar e.g. would, but they 
don't offer a library...

Anyway, thanks for having a look. If there is a great library or archive 
format that should e considered feel free to bring it up.

I just had a look at the XAR format (used by rpm5) but development also 
already has slowed down while some issues are still open (like creating 
the promissed DTD). It also has the disadvantage of pulling in a long 
tail of dependencies.

In general I thing a format without an index and without internal 
compression (as cpio or tar) fits the RPM use case better than formats 
with an file index at the end or the beginning that use by file compression.
As we typically package lots of small files I expect the compression 
rate to significantly drop when switching to by file compression. But I 
cannot back that up with real data right now.


Reg. Adresse: Red Hat GmbH, Hauptstätter Str. 58, 70178 Stuttgart
Handelsregister: Amtsgericht Muenchen HRB 153243
Geschaeftsfuehrer: Brendan Lane, Charlie Peters, Michael Cunningham,
Charles Cachera

More information about the Rpm-maint mailing list