GZIP File Format and Implementations
– gzip is based on the DEFLATE algorithm, a combination of LZ77 and Huffman coding.
– gzip file format consists of a 10-byte header, including a magic number, compression method, and timestamp.
– The file format allows for optional extra headers, such as the original filename and comment field.
– The body of the file contains a DEFLATE-compressed payload.
– The file ends with an 8-byte trailer containing a CRC-32 checksum and the length of the original uncompressed data.
– NetBSD Gzip, FreeBSD Gzip, and OpenBSD’s version of gzip are implementations of gzip.
– Zopfli is an alternative compression program that achieves better compression but requires more time.
– pigz, written by Mark Adler, is compatible with gzip and speeds up compression using multiple CPU cores and threads.
Damage Recovery and Derivatives
– Data in blocks before the damaged part of the archive is usually fully readable.
– Data from blocks after the damaged part may be recoverable through difficult workarounds.
– The tar utility can extract .tar.gz files by using the ‘z’ option.
– zlib is an abstraction of the DEFLATE algorithm and supports the gzip file format.
– The gzip format is used in HTTP compression to speed up content delivery on the web.
– bzip2 is a gzip replacement that produces smaller files but requires more memory and processing time.
– AdvanceCOMP and 7-Zip can produce gzip-compatible files with better compression ratios.
GZIP File Format Specification
– RFC 1952 is the GZIP file format specification version 4.3.
– GZIP files have the extension .dmg or .egg.
– The GZIP file format specification is an industry standard.
– The specification provides guidelines for compressing and decompressing files.
Contributors to GZIP
– Alexandre Oliva, Benjamin Mako Hill, Bradley M. Kuhn, Brian Fox, and Federico Heinz have contributed to the development of GZIP.
Importance and Alternatives of GZIP
– GZIP is widely used for file compression on the internet.
– GZIP helps reduce the size of files for faster transmission.
– Compressed files using GZIP can be easily decompressed.
– GZIP is compatible with various operating systems and platforms.
– GZIP is an essential tool for efficient data storage and transfer.
– ZIP, BZIP2, LZMA, Zstandard (Zstd), and 7-Zip are alternative file compression formats to GZIP.
Applications of GZIP
– GZIP is often used in web servers to compress data before sending it to clients.
– GZIP is utilized in backup and archiving tools to reduce file sizes.
– GZIP is employed in software distribution to compress installation packages.
– GZIP is used in various file formats, including TAR, to reduce storage requirements.
gzip is a file format and a software application used for file compression and decompression. The program was created by Jean-loup Gailly and Mark Adler as a free software replacement for the compress program used in early Unix systems, and intended for use by GNU (from where the "g" of gzip is derived). Version 0.1 was first publicly released on 31 October 1992, and version 1.0 followed in February 1993.
|31 October 1992
|Unix-like, Plan 9, Inferno
1912 NW 143rd Ave #24,
Portland, OR 97229, USA