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Compression formats

David Haslam
Have the SWORD developers ever considered adding support for the 7z open compression format?

See http://www.7-zip.org/7z.html

Best regards,

David
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Re: Compression formats

Greg Hellings
7z is a file format, not a compression format. As such, it is not really relevant to SWORD, except as a possible method for distributing archives of files (e.g. in lieu of a tar.gz of the conf files or a zip of an entire module). For those few specific cases where we distribute archives, 7z does not benefit us as much as either zip or tar, since those two are supported native formats in our target operating systems.

7z does support more efficient compression algorithms than, for example, zip files support. However, since our modules are typically already compressed we are more in need of an easily accessible archive format. 7z is an archive format, but it's not as easily accessible as zip. Compressing an already compressed file generally yields very poor, if any, improvement on the existing compression.

Thus, 7z isn't really useful for SWORD's purposes. We already support its better algorithms (LZMA) in the engine for compressing the modules. Our additional needs are simply to distribute archive files of those compressed modules, where our goal is ease of access to the format rather than re-compressing the modules. The only additional benefit of compressing the modules in the archive is compression of the conf file. On the whole, the relative size of that component is miniscule compared to the module it's accompanying, so gzip or zip compression is more than sufficient to tack onto the archive file.

--Greg

On Mon, Apr 17, 2017 at 10:43 AM, David Haslam <[hidden email]> wrote:
Have the SWORD developers ever considered adding support for the *7z* open
compression format?

See http://www.7-zip.org/7z.html

Best regards,

David



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Re: Compression formats

DM Smith-5
We also support xz and bz2 with the next release. Already in JSword.
-- DM 

On Apr 17, 2017, at 12:06 PM, Greg Hellings <[hidden email]> wrote:

7z is a file format, not a compression format. As such, it is not really relevant to SWORD, except as a possible method for distributing archives of files (e.g. in lieu of a tar.gz of the conf files or a zip of an entire module). For those few specific cases where we distribute archives, 7z does not benefit us as much as either zip or tar, since those two are supported native formats in our target operating systems.

7z does support more efficient compression algorithms than, for example, zip files support. However, since our modules are typically already compressed we are more in need of an easily accessible archive format. 7z is an archive format, but it's not as easily accessible as zip. Compressing an already compressed file generally yields very poor, if any, improvement on the existing compression.

Thus, 7z isn't really useful for SWORD's purposes. We already support its better algorithms (LZMA) in the engine for compressing the modules. Our additional needs are simply to distribute archive files of those compressed modules, where our goal is ease of access to the format rather than re-compressing the modules. The only additional benefit of compressing the modules in the archive is compression of the conf file. On the whole, the relative size of that component is miniscule compared to the module it's accompanying, so gzip or zip compression is more than sufficient to tack onto the archive file.

--Greg

On Mon, Apr 17, 2017 at 10:43 AM, David Haslam <[hidden email]> wrote:
Have the SWORD developers ever considered adding support for the *7z* open
compression format?

See http://www.7-zip.org/7z.html

Best regards,

David



--
View this message in context: http://sword-dev.350566.n4.nabble.com/Compression-formats-tp4657076.html
Sent from the SWORD Dev mailing list archive at Nabble.com.

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