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Diffstat (limited to 'doc/plzip.texinfo')
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1 files changed, 57 insertions, 49 deletions
diff --git a/doc/plzip.texinfo b/doc/plzip.texinfo index 8867c7f..517dc11 100644 --- a/doc/plzip.texinfo +++ b/doc/plzip.texinfo @@ -5,8 +5,8 @@ @finalout @c %**end of header -@set UPDATED 20 March 2010 -@set VERSION 0.6 +@set UPDATED 3 December 2010 +@set VERSION 0.7 @dircategory Data Compression @direntry @@ -14,9 +14,10 @@ @end direntry +@ifnothtml @titlepage @title Plzip -@subtitle A data compressor based on the LZMA algorithm +@subtitle Parallel compressor compatible with lzip @subtitle for Plzip version @value{VERSION}, @value{UPDATED} @author by Antonio Diaz Diaz @@ -25,6 +26,7 @@ @end titlepage @contents +@end ifnothtml @node Top @top @@ -32,12 +34,12 @@ This manual is for Plzip (version @value{VERSION}, @value{UPDATED}). @menu -* Introduction:: Purpose and features of plzip -* Invoking Plzip:: Command line interface -* Program Design:: Internal structure of plzip -* File Format:: Detailed format of the compressed file -* Problems:: Reporting bugs -* Concept Index:: Index of concepts +* Introduction:: Purpose and features of plzip +* Invoking Plzip:: Command line interface +* Program Design:: Internal structure of plzip +* File Format:: Detailed format of the compressed file +* Problems:: Reporting bugs +* Concept Index:: Index of concepts @end menu @sp 1 @@ -52,10 +54,10 @@ to copy, distribute and modify it. @cindex introduction Plzip is a massively parallel (multi-threaded), lossless data compressor -based on the LZMA algorithm, with very safe integrity checking and a -user interface similar to the one of gzip or bzip2. Plzip uses the lzip -file format; the files produced by plzip are fully compatible with -lzip-1.4 or newer. +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. Plzip is intended for faster compression/decompression of big files on multiprocessor machines, which makes it specially well suited for @@ -121,77 +123,77 @@ plzip [@var{options}] [@var{files}] Plzip supports the following options: @table @samp -@item --help -@itemx -h +@item -h +@itemx --help Print an informative help message describing the options and exit. -@item --version -@itemx -V +@item -V +@itemx --version Print the version number of plzip on the standard output and exit. -@item --data-size=@var{size} -@itemx -B +@item -B +@itemx --data-size=@var{size} Set the input data block size in bytes. The input file will be divided in chunks of this size before compression is performed. Valid values range from 8KiB to 1GiB. Default value is two times the dictionary size. Plzip will reduce the dictionary size if it is larger than the chosen data size. -@item --stdout -@itemx -c +@item -c +@itemx --stdout Compress or decompress to standard output. Needed when reading from a named pipe (fifo) or from a device. -@item --decompress -@itemx -d +@item -d +@itemx --decompress Decompress. -@item --force -@itemx -f +@item -f +@itemx --force Force overwrite of output file. -@item --keep -@itemx -k +@item -k +@itemx --keep Keep (don't delete) input files during compression or decompression. -@item --match-length=@var{length} -@itemx -m @var{length} +@item -m @var{length} +@itemx --match-length=@var{length} Set the match length limit in bytes. Valid values range from 5 to 273. Larger values usually give better compression ratios but longer compression times. -@item --threads=@var{threads} -@itemx -n @var{threads} +@item -n @var{threads} +@itemx --threads=@var{threads} Set the number of worker threads. Valid values range from 1 to "as many as your system can support". If this option is not used, plzip tries to detect the number of processors in the system and use it as default value. -@item --output=@var{file} -@itemx -o @var{file} +@item -o @var{file} +@itemx --output=@var{file} When reading from standard input and @samp{--stdout} has not been specified, use @samp{@var{file}} as the virtual name of the uncompressed file. This produces a file named @samp{@var{file}} when decompressing, and a file named @samp{@var{file}.lz} when compressing. -@item --quiet -@itemx -q +@item -q +@itemx --quiet Quiet operation. Suppress all messages. -@item --dictionary-size=@var{size} -@itemx -s @var{size} +@item -s @var{size} +@itemx --dictionary-size=@var{size} Set the dictionary size limit in bytes. Valid values range from 4KiB to 512MiB. Note that dictionary sizes are quantized. If the specified size does not match one of the valid sizes, it will be rounded upwards. -@item --test -@itemx -t +@item -t +@itemx --test Check integrity of the specified file(s), but don't decompress them. This really performs a trial decompression and throws away the result. Use @samp{-tvv} or @samp{-tvvv} to see information about the file. -@item --verbose -@itemx -v +@item -v +@itemx --verbose Verbose mode. Show the compression ratio for each file processed. Further -v's increase the verbosity level. @@ -200,16 +202,22 @@ Set the compression parameters (dictionary size and match length limit) as shown in the table below. Note that @samp{-9} can be much slower than @samp{-1}. These options have no effect when decompressing. +The bidimensional parameter space of LZMA can't be mapped to a linear +scale optimal for all files. If your files are large, very repetitive, +etc, you may need to use the @samp{--match-length} and +@samp{--dictionary-size} options directly to achieve optimal +performance. + @multitable {Level} {Dictionary size} {Match length limit} @item Level @tab Dictionary size @tab Match length limit -@item -1 @tab 1 MiB @tab 10 bytes -@item -2 @tab 1.5 MiB @tab 12 bytes -@item -3 @tab 2 MiB @tab 17 bytes -@item -4 @tab 3 MiB @tab 26 bytes -@item -5 @tab 4 MiB @tab 44 bytes -@item -6 @tab 8 MiB @tab 80 bytes -@item -7 @tab 16 MiB @tab 108 bytes -@item -8 @tab 24 MiB @tab 163 bytes +@item -1 @tab 1 MiB @tab 5 bytes +@item -2 @tab 1.5 MiB @tab 6 bytes +@item -3 @tab 2 MiB @tab 8 bytes +@item -4 @tab 3 MiB @tab 12 bytes +@item -5 @tab 4 MiB @tab 20 bytes +@item -6 @tab 8 MiB @tab 36 bytes +@item -7 @tab 16 MiB @tab 68 bytes +@item -8 @tab 24 MiB @tab 132 bytes @item -9 @tab 32 MiB @tab 273 bytes @end multitable |