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@@ -3,13 +3,18 @@ Description Plzip is a massively parallel (multi-threaded), lossless data compressor based on the lzlib compression library, with very safe integrity checking and a user interface similar to the one of bzip2, gzip or lzip. -Plzip uses the lzip file format; the files produced by plzip are fully -compatible with lzip-1.4 or newer, and can be rescued with lziprecover. Plzip is intended for faster compression/decompression of big files on multiprocessor machines, which makes it specially well suited for distribution of big software files and large scale data archiving. On -files big enough, plzip can use hundreds of processors. +files big enough (several GB), plzip can use hundreds of processors. + +Plzip uses the lzip file format; the files produced by plzip are fully +compatible with lzip-1.4 or newer, and can be rescued with lziprecover. + +Plzip uses the same well-defined exit status values used by lzip and +bzip2, which makes it safer when used in pipes or scripts than +compressors returning ambiguous warning values, like gzip. Plzip replaces every file given in the command line with a compressed version of itself, with the name "original_name.lz". Each compressed @@ -29,15 +34,16 @@ corresponding uncompressed files. Integrity testing of concatenated compressed files is also supported. As a self-check for your protection, plzip stores in the member trailer -the 32-bit CRC of the original data and the size of the original data, -to make sure that the decompressed version of the data is identical to -the original. This guards against corruption of the compressed data, and -against undetected bugs in plzip (hopefully very unlikely). The chances -of data corruption going undetected are microscopic, less than one -chance in 4000 million for each member processed. Be aware, though, that -the check occurs upon decompression, so it can only tell you that -something is wrong. It can't help you recover the original uncompressed -data. +the 32-bit CRC of the original data, the size of the original data and +the size of the member. These values, together with the value remaining +in the range decoder and the end-of-stream marker, provide a very safe 4 +factor integrity checking which guarantees that the decompressed version +of the data is identical to the original. This guards against corruption +of the compressed data, and against undetected bugs in plzip (hopefully +very unlikely). The chances of data corruption going undetected are +microscopic. Be aware, though, that the check occurs upon decompression, +so it can only tell you that something is wrong. It can't help you +recover the original uncompressed data. Copyright (C) 2009, 2010, 2011, 2012, 2013 Antonio Diaz Diaz. |