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Description
Lziprecover is a data recovery tool and decompressor for files in the
-lzip compressed data format (.lz) able to repair slightly damaged files,
-recover badly damaged files from two or more copies, extract data from
-damaged files, decompress files and test integrity of files.
+lzip compressed data format (.lz), able to repair slightly damaged
+files, recover badly damaged files from two or more copies, extract data
+from damaged files, decompress files and test integrity of files.
+
+The lzip file format is designed for long-term data archiving. It is
+clean, provides very safe 4 factor integrity checking, and is backed by
+the recovery capabilities of lziprecover.
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. It makes lzip files resistant to bit-flip, one of the most
-common forms of data corruption, and its recovery capabilities
-contribute to make of the lzip format one of the best options for
-long-term data archiving.
+and pdlzip.
+
+Lziprecover makes lzip files resistant to bit-flip (one of the most
+common forms of data corruption), and can safely merge multiple damaged
+backup copies.
+
+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 a file is too damaged for lziprecover to repair it, all the
+recoverable data in all members of the file can be extracted with the
+'-D' option.
Lziprecover is able to efficiently extract a range of bytes from a
multi-member file, because it only decompresses the members containing
@@ -27,24 +40,20 @@ damaged files themselves are never modified.
When decompressing or testing file integrity, lziprecover behaves like
lzip or lunzip.
-If the files are too damaged for lziprecover to repair them, data from
-damaged members can be partially recovered writing it to stdout.
-
-To give you an idea of its possibilities, when merging two copies each
+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 with
-small errors, the probability approaches 100 percent even with only two
-copies.
+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.
-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.
+Lziprecover is not a replacement for regular backups, but a last line of
+defense for the case where the backups are also damaged.
-This 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
-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, 2010, 2011, 2012, 2013 Antonio Diaz Diaz.