jerome.bouat: 07:29 Oct 08, 2009
On my Ubuntu karmic Linux distribution, the /usr/share/ppd directory uses a lot of disk space.
All the ppd files are currently compressed by using gzip.
I think that using lzma would decrease the used disk space as well as improve the decompression speed.
Below is a comparaison for the file /usr/share/ppd/openprinting/KONICA_MINOLTA/KO1050UX.ppd.gz:
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j@j-desktop:~$ du KO1050UX.ppd*
256 KO1050UX.ppd
24 KO1050UX.ppd.gz
16 KO1050UX.ppd.lzma
j@j-desktop:~$ time { for i in {0..999} ; do unlzma -c KO1050UX.ppd.lzma >/dev/null ; done }
real 0m18.765s
user 0m7.060s
sys 0m11.560s
j@j-desktop:~$ time { for i in {0..999} ; do gunzip -c KO1050UX.ppd.gz >/dev/null ; done }
real 0m23.183s
user 0m6.840s
sys 0m16.170s
j@j-desktop:~$
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I posted a feature request to my Linux distribution here:
https://bugs.launchpad.net/ubuntu/+source/foomatic-db/+bug/446245
Unfortunately I was told that those ppd files couldn't be compressed with lzma because cups was able to read only the gzip compression format.
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mike: 09:48 Oct 09, 2009
This is an interesting idea, but don't expect this to be implemented any time soon. Among other things we'll need to integrate support for this into the CUPS file APIs and be able to do auto-detection of the compression format when reading.
LZMA as a format has also not been standardized like GZIP/Flate, so we'd want to make sure that issue is covered before we adopt it.
Link to public SDK:
http://www.7-zip.org/sdk.html
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mike: 09:53 Oct 09, 2009
Also XZ Tools (replacement for LZMA Tools):
http://tukaani.org/xz/
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jerome.bouat: 10:26 Oct 12, 2009
tar is supporting lzma with a --lzma option. I think this is a kind of standardization.
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mike: 12:03 Jan 12, 2012
Sorry, we have decided this issue will not be addressed in a CUPS release.
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mike: 12:05 Mar 06, 2012
Reopening this based on our investigations into STR #3772. Not for CUPS 1.6, but perhaps a later release.
The goal will be to add support for LZMA/XZ to the CUPS file APIs so that we can use this for all files, not just PPDs and archives of PPDs.
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