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authorDaniel Baumann <daniel.baumann@progress-linux.org>2021-01-25 13:52:00 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2021-01-25 13:52:20 +0000
commitf0bda7c287ad4012750724d1a836131e6498d9a9 (patch)
treec4a0925d3fbb0aef25524ccd6689e2595c8896b2 /README
parentReleasing debian version 1.21-9. (diff)
downloadlziprecover-f0bda7c287ad4012750724d1a836131e6498d9a9.tar.xz
lziprecover-f0bda7c287ad4012750724d1a836131e6498d9a9.zip
Merging upstream version 1.22.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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diff --git a/README b/README
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@@ -3,8 +3,9 @@ Description
Lziprecover is a data recovery tool and decompressor for files in the lzip
compressed data format (.lz). Lziprecover is able to repair slightly damaged
files, produce a correct file by merging the good parts of two or more
-damaged copies, extract data from damaged files, decompress files and test
-integrity of files.
+damaged copies, reproduce a missing (zeroed) sector using a reference file,
+extract data from damaged files, decompress files, and test integrity of
+files.
Lziprecover can remove the damaged members from multimember files, for
example multimember tar.lz archives.
@@ -22,68 +23,71 @@ The lzip file format is designed for data sharing and long-term archiving,
taking into account both data integrity and decoder availability:
* The lzip format provides very safe integrity checking and some data
- recovery means. The lziprecover program can repair bit flip errors
- (one of the most common forms of data corruption) in lzip files,
- and provides data recovery capabilities, including error-checked
- merging of damaged copies of a file.
-
- * The lzip format is as simple as possible (but not simpler). The
- lzip manual provides the source code of a simple decompressor
- along with a detailed explanation of how it works, so that with
- the only help of the lzip manual it would be possible for a
- digital archaeologist to extract the data from a lzip file long
- after quantum computers eventually render LZMA obsolete.
+ recovery means. The program lziprecover can repair bit flip errors
+ (one of the most common forms of data corruption) in lzip files, and
+ provides data recovery capabilities, including error-checked merging
+ of damaged copies of a file.
+
+ * The lzip format is as simple as possible (but not simpler). The lzip
+ manual provides the source code of a simple decompressor along with a
+ detailed explanation of how it works, so that with the only help of the
+ lzip manual it would be possible for a digital archaeologist to extract
+ the data from a lzip file long after quantum computers eventually
+ render LZMA obsolete.
* Additionally the lzip reference implementation is copylefted, which
guarantees that it will remain free forever.
-A nice feature of the lzip format is that a corrupt byte is easier to
-repair the nearer it is from the beginning of the file. Therefore, with
-the help of lziprecover, losing an entire archive just because of a
-corrupt byte near the beginning is a thing of the past.
+A nice feature of the lzip format is that a corrupt byte is easier to repair
+the nearer it is from the beginning of the file. Therefore, with the help of
+lziprecover, losing an entire archive just because of a corrupt byte near
+the beginning is a thing of the past.
-For compressible data, multiple lzip-compressed copies have a better
-chance of surviving intact than one uncompressed copy using the same
-amount of storage space.
+Compression may be good for long-term archiving. For compressible data,
+multiple compressed copies may provide redundancy in a more useful form and
+may have a better chance of surviving intact than one uncompressed copy
+using the same amount of storage space. This is specially true if the format
+provides recovery capabilities like those of lziprecover, which is able to
+find and combine the good parts of several damaged copies.
-Lziprecover is able to recover or decompress files produced by any of
-the compressors in the lzip family; lzip, plzip, minilzip/lzlib, clzip
-and pdlzip.
+Lziprecover is able to recover or decompress files produced by any of the
+compressors in the lzip family; lzip, plzip, minilzip/lzlib, clzip, and
+pdlzip.
-If the cause of file corruption is damaged media, the combination
-GNU ddrescue + lziprecover is the best option for recovering data from
-multiple damaged copies.
+If the cause of file corruption is a damaged medium, the combination
+GNU ddrescue + lziprecover is the recommended option for recovering data
+from damaged lzip files.
-If a file is too damaged for lziprecover to repair it, all the
-recoverable data in all members of the file can be extracted in one step
-with the '-D' option.
+If a file is too damaged for lziprecover to repair it, all the recoverable
+data in all members of the file can be extracted in one step with the
+command 'lziprecover -cd -i file.lz > file'.
When recovering data, lziprecover takes as arguments the names of the
damaged files and writes zero or more recovered files depending on the
-operation selected and whether the recovery succeeded or not. The
-damaged files themselves are kept unchanged.
+operation selected and whether the recovery succeeded or not. The damaged
+files themselves are kept unchanged.
-When decompressing or testing file integrity, lziprecover behaves like
-lzip or lunzip.
+When decompressing or testing file integrity, lziprecover behaves like lzip
+or lunzip.
-To give you an idea of its possibilities, when merging two copies, each
-of them with one damaged area affecting 1 percent of the copy, the
-probability of obtaining a correct file is about 98 percent. With three
-such copies the probability rises to 99.97 percent. For large files (a
-few MB) with small errors (one sector damaged per copy), the probability
-approaches 100 percent even with only two copies. (Supposing that the
-errors are randomly located inside each copy).
+To give you an idea of its possibilities, when merging two copies, each of
+them with one damaged area affecting 1 percent of the copy, the probability
+of obtaining a correct file is about 98 percent. With three such copies the
+probability rises to 99.97 percent. For large files (a few MB) with small
+errors (one sector damaged per copy), the probability approaches 100 percent
+even with only two copies. (Supposing that the errors are randomly located
+inside each copy).
-The lziprecover package also includes unzcrash, a program written to
-test robustness to decompression of corrupted data, inspired by
-unzcrash.c from Julian Seward's bzip2. Type 'make unzcrash' in the
-lziprecover source directory to build it. Then try 'unzcrash --help'.
+The lziprecover package also includes unzcrash, a program written to test
+robustness to decompression of corrupted data, inspired by unzcrash.c from
+Julian Seward's bzip2. Type 'make unzcrash' in the lziprecover source
+directory to build it. Then try 'unzcrash --help'.
-Copyright (C) 2009-2019 Antonio Diaz Diaz.
+Copyright (C) 2009-2021 Antonio Diaz Diaz.
This file is free documentation: you have unlimited permission to copy,
-distribute and modify it.
+distribute, and modify it.
The file Makefile.in is a data file used by configure to produce the
Makefile. It has the same copyright owner and permissions that configure