Jigdo?

[chrisw at chiark.greenend.org.uk (Chris Walker)]

Hi Alex,

On Wed, Aug 06, 2008 at 05:19:43PM +0100, Alex Owen wrote:
> My understanding of jogdo is that it is for ISO's that contain *.deb packages...
> ISO's are essentially a concatination of the *.debs with some metadata
> wrapper to make the iso.

Jigdo is more generic than that though[1]. It will generate a large file from
bits of small files (and may be able to cope with parts of these
files, I'm not sure). 

> 
> The live cd contains UNPAKED debs... so could not work.


It certainly won't work out of the box. 

In theory though, jigdo could be modified to read inside a compressed file,
such as a .deb (which is an "ar" archive containing several .tar.gz files)

More difficult, is that the live cd is on a compressed filesystem. To
generate an exact copy, something akin to
http://kitenet.net/~joey/code/pristine-tar/ would also be needed. 

I guess I sent the mail when I did in the hope that Frederic might
chat to Joey Hess at Debconf and Richard Atterer about how difficult
this might be.

One further pipedream. AIUI, it is currently possible to make a
combined liveDVD with installer, but it contains the same data twice
(as a .deb and unpacked). Pristine-tar could permit the data to be
stored only once (if adapted to cope with the deb file format).

> 
> I could have missed the whole thechnology behind jigdo though...!


[1] For completeness, Steve McIntyre's JTE extension to mkisofs uses
the fact that ISOs are concatenations of .debs with metadata to
generate jigdo files on the fly. This gives a considerable speedup
apparently.


Chris


> 
> 2008/8/6 Frederic Lehobey <Frederic at lehobey.net>:
> > Hi,
> >
> > Chris Walker has just suggested to me that Live isos could be
> > downloaded with Jigdo. Have you ever thought about it? Does it sound
> > sensible / possible?
> >
> > Best regards,
> > Fr?d?ric
> >
> >
> >
> > _______________________________________________
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> >