Re: Migrations to xorriso

["Vladimir 'φ-coder/phcoder' Serbinenko" <phcoder@gmail.com>]

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Thomas Schmitt wrote:
> Hi,
>
> Isaac Dupree wrote:
>   
>> What size range are the whole images? 
>>     
>
> The minimum output of grub-mkrescue 1.98 with
> xorriso is 1544192 bytes.
> grub-mkisofs: 1550336
> genisoimage:  1859584 (-307200 with -no-pad)
>
> One may add lots of other files, of course.
>
>
>   
>> Also I guess no one compresses whole ISOs
>>     
>
> It makes few sense to compress the ISO as a
> whole. But one could compress some files in it.
>
> One could implement a reader for H. Peter Anvin's
> zisofs format in GRUB's ISO 9660 reader - if not
> present already.
> zisofs is a transparent content compression of
> single files. A reader is implemented in the
> Linux kernel. See macro CONFIG_ZISOFS in
> fs/isofs/*.[ch].
> An authorised description is given in
> doc/zisofs_format.txt of xorriso resp. in
>   http://bazaar.launchpad.net/~libburnia-team/libisofs/scdbackup/annotate/head:/doc/zisofs_format.txt
> The ISO 9660 directory tree stays uncompressed.
> Compressed and uncompressed files can be mixed.
>
> xorriso can produce zisofs compressed data files
> on the fly (needs zlib).
> A grub-mkrescue 1.98 image with all files
> compressed has 884736 bytes. But one would have
> to leave those files uncompressed which are
> needed for reading ISO 9660 and zisofs
> compression.
>
>   
I'm not sure that zisofs is useful for grub. We already have support for
.gz files. xz support is coming. Compressing explicitly we would avoid
to accidently compressing files we need uncompressed. Also we're more
fs-independent.
Implementing zisofs reader may have some value but isn't a priority.
> Have a nice day :)
>
> Thomas
>  
>
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>
>   


-- 
Regards
Vladimir 'φ-coder/phcoder' Serbinenko



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