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Re: sunsite.org.uk - rsync access to cd-images

On Tue, 17 Aug 1999, J.A. Bezemer wrote:

>There is however another easier and more robust way of making a
>pseudo-image that can be rsync-patched. 
>ISO images store files in 2048-byte blocks. If all directories are
>located in the beginning of the image, then the rest of the image would
>be a simple concatenation of files that are zero-padded to a multiple of
>2048 bytes. 
>So, if we know which files are in what sequence in the "files part" of
>the image, then it would be very easy to get those files from the nearest
>_packages_ mirror (many fast ones available), pad them to a multiple of
>2048 bytes and cat >>pseudo-image. A very simple shell script using wget
>could do it. No scaring debian_cd/yacs stuff. And it would not require
>any more disk-space than the final image's size. 
>After this, rsync can be used to insert the directory structure,
>Packages.cd files and possibly a few other things. 
> - a sequence-listing of the files on the various CDs should be available on
>   the cdimage sites. The `isoinfo' program from the "cdrecord suite"
>   (http://www.fokus.gmd.de/nthp/employees/schilling/cdrecord.html) can
>   generate such a listing from the ISO image;
> - a simple script for the "cd burner" that uses this listing to build a
>   pseudo-image as described above;
> - understandable & correct instructions how to use rsync to patch
>   the pseudo-image to an Official one.
>Would this approach work?

Hmmm. Interesting. It could well do...

>At the moment, I've only limited net access, and loads of other things to
>do, so I'll leave it to a volunteer to further explore this. 


>BTW, this works best if all directories are located at the beginning of the
>image. `mkisofs' 1.12b3 as distributed in the "cdrecord suite" (see above)
>does this; I'm not sure about `mkhybrid'. BTW, do you really still use
>`mkhybrid'? The new `mkisofs' seems to be able to do anything `mkhybrid'

Does it flatten external sym-links if necessary?

>Another question: does rsync patch in-place or does it make a temporary
>patched file (thus requiring twice the disk space)?

It patches in-place.

Steve McIntyre, Allstor Software         smcintyr@allstor-sw.co.uk
<a href=http://www.chiark.greenend.org.uk/~stevem/comp/>My PC page</a>
"Can't keep my eyes from the circling sky,                 
"Tongue-tied & twisted, Just an earth-bound misfit, I..."  

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