A file archiver is a computer program that combines a number of files together into one archive file, or a series of archive files, for easier transportation or storage. File archivers may employ lossless data compression in their archive formats to reduce the size of the archive.
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. Version 0.1 was first publicly released on 31 October 1992, and version 1.0 followed in February 1993.
In computing, tar is a computer software utility for collecting many files into one archive file, often referred to as a tarball, for distribution or backup purposes. The name is derived from "tape archive", as it was originally developed to write data to sequential I/O devices with no file system of their own, such as devices that use magnetic tape. The archive data sets created by tar contain various file system parameters, such as name, timestamps, ownership, file-access permissions, and directory organization. POSIX abandoned tar in favor of pax, yet tar sees continued widespread use.
compress is a Unix shell compression program based on the LZW compression algorithm. Compared to gzip's fastest setting, compress is slightly slower at compression, slightly faster at decompression, and has a significantly lower compression ratio. 1.8 MiB of memory is used to compress the Hutter Prize data, slightly more than gzip's slowest setting.
7-Zip is a free and open-source file archiver, a utility used to place groups of files within compressed containers known as "archives". It is developed by Igor Pavlov and was first released in 1999. 7-Zip has its own archive format called 7z, but can read and write several others.
rzip is a huge-scale data compression computer program designed around initial LZ77-style string matching on a 900 MB dictionary window, followed by bzip2-based Burrows–Wheeler transform and entropy coding (Huffman) on 900 kB output chunks.
vmlinux is a statically linked executable file that contains the Linux kernel in one of the object file formats supported by Linux, which includes Executable and Linkable Format (ELF) and Common Object File Format (COFF). The vmlinux file might be required for kernel debugging, symbol table generation or other operations, but must be made bootable before being used as an operating system kernel by adding a multiboot header, bootsector and setup routines.
The following tables compare general and technical information for a number of file archivers. Please see the individual products' articles for further information. They are neither all-inclusive nor are some entries necessarily up to date. Unless otherwise specified in the footnotes section, comparisons are based on the stable versions—without add-ons, extensions or external programs.
Executable compression is any means of compressing an executable file and combining the compressed data with decompression code into a single executable. When this compressed executable is executed, the decompression code recreates the original code from the compressed code before executing it. In most cases this happens transparently so the compressed executable can be used in exactly the same way as the original. Executable compressors are often referred to as "runtime packers", "software packers", "software protectors".
dar is a computer program, a command-line archiving tool intended as a replacement for tar in Unix-like operating systems.
Snappy is a fast data compression and decompression library written in C++ by Google based on ideas from LZ77 and open-sourced in 2011. It does not aim for maximum compression, or compatibility with any other compression library; instead, it aims for very high speeds and reasonable compression. Compression speed is 250 MB/s and decompression speed is 500 MB/s using a single core of a circa 2011 "Westmere" 2.26 GHz Core i7 processor running in 64-bit mode. The compression ratio is 20–100% lower than gzip.
In Linux systems, initrd is a scheme for loading a temporary root file system into memory, to be used as part of the Linux startup process. initrd and initramfs refer to two different methods of achieving this. Both are commonly used to make preparations before the real root file system can be mounted.
Squashfs is a compressed read-only file system for Linux. Squashfs compresses files, inodes and directories, and supports block sizes from 4 KiB up to 1 MiB for greater compression. Several compression algorithms are supported. Squashfs is also the name of free software, licensed under the GPL, for accessing Squashfs filesystems.
PeaZip is a free and open-source file manager and file archiver for Microsoft Windows, ReactOS, Linux, MacOS and BSD by Giorgio Tani. It supports its native PEA archive format and other mainstream formats, with special focus on handling open formats. Version 9.4.0 supported 234 file extensions.
Xarchiver is a front-end to various command line archiving tools for Linux and BSD operating systems, designed to be independent of the desktop environment. It is the default archiving application of Xfce and LXDE. Deepin's archive manager is based on Xarchiver.
XZ Utils is a set of free software command-line lossless data compressors, including the programs lzma and xz, for Unix-like operating systems and, from version 5.0 onwards, Microsoft Windows. For compression/decompression the Lempel–Ziv–Markov chain algorithm (LZMA) is used. XZ Utils started as a Unix port of Igor Pavlov's LZMA-SDK that has been adapted to fit seamlessly into Unix environments and their usual structure and behavior.
zram, formerly called compcache, is a Linux kernel module for creating a compressed block device in RAM, i.e. a RAM disk with on-the-fly disk compression. The block device created with zram can then be used for swap or as general-purpose RAM disk. The two most common uses for zram are for the storage of temporary files and as a swap device. Initially, zram had only the latter function, hence the original name "compcache".
LZ4 is a lossless data compression algorithm that is focused on compression and decompression speed. It belongs to the LZ77 family of byte-oriented compression schemes.
