diff options
Diffstat (limited to 'README')
| -rw-r--r-- | README | 51 |
1 files changed, 26 insertions, 25 deletions
@@ -1,18 +1,19 @@ Description -Plzip is a massively parallel (multi-threaded) implementation of lzip, fully +Plzip is a massively parallel (multi-threaded) implementation of lzip, compatible with lzip 1.4 or newer. Plzip uses the compression library lzlib. Lzip is a lossless data compressor with a user interface similar to the one of gzip or bzip2. Lzip uses a simplified form of the 'Lempel-Ziv-Markov -chain-Algorithm' (LZMA) stream format and provides a 3 factor integrity -checking to maximize interoperability and optimize safety. Lzip can compress -about as fast as gzip (lzip -0) or compress most files more than bzip2 -(lzip -9). Decompression speed is intermediate between gzip and bzip2. -Lzip is better than gzip and bzip2 from a data recovery perspective. Lzip -has been designed, written, and tested with great care to replace gzip and -bzip2 as the standard general-purpose compressed format for unix-like -systems. +chain-Algorithm' (LZMA) stream format to maximize interoperability. The +maximum dictionary size is 512 MiB so that any lzip file can be decompressed +on 32-bit machines. Lzip provides accurate and robust 3-factor integrity +checking. Lzip can compress about as fast as gzip (lzip -0) or compress most +files more than bzip2 (lzip -9). Decompression speed is intermediate between +gzip and bzip2. Lzip is better than gzip and bzip2 from a data recovery +perspective. Lzip has been designed, written, and tested with great care to +replace gzip and bzip2 as the standard general-purpose compressed format for +Unix-like systems. Plzip can compress/decompress large files on multiprocessor machines much faster than lzip, at the cost of a slightly reduced compression ratio (0.4 @@ -27,11 +28,12 @@ alignment between tar members and lzip members. When compressing, plzip divides the input file into chunks and compresses as many chunks simultaneously as worker threads are chosen, creating a -multimember compressed file. +multimember compressed file. Each chunk is compressed in-place (using the +same buffer for input and output), reducing the amount of RAM required. When decompressing, plzip decompresses as many members simultaneously as -worker threads are chosen. Files that were compressed with lzip will not -be decompressed faster than using lzip (unless the option '-b' was used) +worker threads are chosen. Files that were compressed with lzip are not +decompressed faster than using lzip (unless the option '-b' was used) because lzip usually produces single-member files, which can't be decompressed in parallel. @@ -63,9 +65,9 @@ Plzip uses the same well-defined exit status values used by lzip, which makes it safer than compressors returning ambiguous warning values (like gzip) when it is used as a back end for other programs like tar or zutils. -Plzip will automatically use for each file the largest dictionary size that -does not exceed neither the file size nor the limit given. Keep in mind that -the decompression memory requirement is affected at compression time by the +Plzip automatically uses for each file the largest dictionary size that does +not exceed neither the file size nor the limit given. Keep in mind that the +decompression memory requirement is affected at compression time by the choice of dictionary size limit. When compressing, plzip replaces every file given in the command line @@ -78,20 +80,20 @@ filename.tlz becomes filename.tar anyothername becomes anyothername.out (De)compressing a file is much like copying or moving it. Therefore plzip -preserves the access and modification dates, permissions, and, when -possible, ownership of the file just as 'cp -p' does. (If the user ID or -the group ID can't be duplicated, the file permission bits S_ISUID and -S_ISGID are cleared). +preserves the access and modification dates, permissions, and, if you have +appropriate privileges, ownership of the file just as 'cp -p' does. (If the +user ID or the group ID can't be duplicated, the file permission bits +S_ISUID and S_ISGID are cleared). Plzip is able to read from some types of non-regular files if either the option '-c' or the option '-o' is specified. If no file names are specified, plzip compresses (or decompresses) from -standard input to standard output. Plzip will refuse to read compressed data +standard input to standard output. Plzip refuses to read compressed data from a terminal or write compressed data to a terminal, as this would be entirely incomprehensible and might leave the terminal in an abnormal state. -Plzip will correctly decompress a file which is the concatenation of two or +Plzip correctly decompresses a file which is the concatenation of two or more compressed files. The result is the concatenation of the corresponding decompressed files. Integrity testing of concatenated compressed files is also supported. @@ -101,11 +103,10 @@ been compressed. Decompressed is used to refer to data which have undergone the process of decompression. -Copyright (C) 2009-2022 Antonio Diaz Diaz. +Copyright (C) 2009-2024 Antonio Diaz Diaz. This file is free documentation: you have unlimited permission to copy, 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 -itself. +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 itself. |