Bug 137305 - For ODT a recovery record against damage of files like winrar 5.xy
Summary: For ODT a recovery record against damage of files like winrar 5.xy
Status: RESOLVED WONTFIX
Alias: None
Product: LibreOffice
Classification: Unclassified
Component: LibreOffice (show other bugs)
Version:
(earliest affected)
unspecified
Hardware: All All
: medium enhancement
Assignee: Not Assigned
URL:
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Keywords:
Depends on:
Blocks:
 
Reported: 2020-10-07 09:01 UTC by paulystefan
Modified: 2020-10-07 10:21 UTC (History)
0 users

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Description paulystefan 2020-10-07 09:01:03 UTC
Winrar has one very good feature
recovery record in the archive file.

Then the user can restore archives with bit failure.
the size of this information is variable.
5% to 10% is a good range.

My idea: an equal feature in Libre Office Files like odt, odm, odf.

or you can use rar containers for odt with 5 to 10% recovery record.



see https://www.rarlab.com/rar_archiver.htm
in news:
RAR 5.0 recovery record is based on Reed-Solomon error correction
      codes. If recovery record size is large enough, 5% and more,
      the new error correction scheme provides much higher resistance to
      multiple damages comparing to RAR 4.x recovery record.
      Smaller record, such as 1 - 2%, or less random damage type would
      result in less difference between 4.x and 5.0. For single continuous
      damage 4.x and 5.0 efficiency is about the same.

      Additionally to usual data erasures, the new recovery record
      is able to detect deletions and insertions of much larger size
      than in previous RAR versions. Maximum insertion size is several
      megabytes. Maximum deletion size depends on the damage type
      and in some cases can be as large as the recovery record size.
      
      Still, the best recovery performance and efficiency is achieved
      if no deletions and insertions are present, so all data including
      damaged sectors preserve their original positions. Thus, if you use
      some special software to copy an archive from damaged media,
      it is better to choose the mode, when damaged sectors are filled by
      zeroes or any other data instead of cutting them out completely
      from resulting file.

      RAR 5.0 recovery record is more resistant to damage of recovery record
      itself and can utilize a partially corrupt recovery record data.
      Note, though, that "Repair" command does not fix broken blocks
      in recovery record. Only file data are corrected. After successful
      archive repair, you may need to create a new recovery record
      for saved files.

      New recovery record is not based on 512 byte sectors anymore 
      and incorporates more complicated data structures. So it is impossible
      to specify its size in sectors. For RAR 5.0 archives the parameter of
      -rr[N] switch and rr[N] command is always treated as a percent of
      archive size regardless of presence of % character. Typically N%
      recovery record can repair up to N% of continuously damaged data
      and increases the archive size by only slightly more than N%.
      Ability to fix multiple damages is proportional to N.

      We used "Screaming Fast Galois Field Arithmetic Using Intel
      SIMD Instructions" paper by James S. Plank, Kevin M. Greenan
      and Ethan L. Miller to improve Reed-Solomon coding performance.
      Also we are grateful to Artem Drobanov and Bulat Ziganshin
      for samples and ideas allowed to make Reed-Solomon coding
      more efficient.
Comment 1 Mike Kaganski 2020-10-07 09:27:43 UTC
ODF uses ZIP for packaging - see respective standard, sect. 2.2.1 [1], which says:

> An OpenDocument Package shall meet the following requirements:
> A) It shall be a Zip file, as defined by [ZIP]. ...

LibreOffice cannot and must not use proprietary undocumented file format, for which only unpack software is freely available, using inappropriate licensing. And ZIP itself does not have the features you are talking about.

So LibreOffice cannot and should not implement this, unless there's a change in the ODF standard. You may of course file necessary proposal to OASIS committee, to make that happen, of course.

[1] http://docs.oasis-open.org/office/OpenDocument/v1.3/OpenDocument-v1.3-part2-packages.html
Comment 2 paulystefan 2020-10-07 09:44:05 UTC
Than it is Time to improve zip.

so you should give this enhancement request to the zip-Community.

This request is with more power by LO-Org, than a small single user like me.
Comment 3 Mike Kaganski 2020-10-07 09:48:30 UTC
(In reply to paulystefan from comment #2)
> so you should give this enhancement request to the zip-Community.
> 
> This request is with more power by LO-Org, than a small single user like me.

Interested parties should do what they are interested in, not expect that they generate ideas, and then others do the legwork.
Comment 4 paulystefan 2020-10-07 10:11:07 UTC
there is only profit by LO-Software and LO-users, when zip is improved with recovery record.

What will LO-Org loose?
So much work to write an email to zip-Organisations?

A cup of tears from me.

Or should I write also to Microsoft.
They must be better than LO-Org.

Is second behind Microsoft the wanted position?

Better with legs and arms than without.
Comment 5 paulystefan 2020-10-07 10:21:42 UTC
this is no luna landing.

open source software parchive have this feature.


https://sourceforge.net/p/sevenzip/discussion/45797/thread/a33a81a5/

https://sourceforge.net/projects/parchive/


better with arms and legs than without.