SquashFS
Developer(s) | Phillip Lougher, Robert Lougher |
---|---|
Introduced | 2009 with Linux 2.6.29 |
Limits | |
Max. volume size | 16 EiB |
Max. file size | 16 EiB |
Features | |
Transparent compression | gzip LZMA LZO LZMA2 LZ4 |
Other | |
Supported operating systems | Linux |
Website | on sourceforge |
SquashFS is a compressed read-only file system for Linux. SquashFS compresses files, inodes and directories, and supports block sizes up to 1 MB for greater compression. SquashFS is also the name of free/open software, licensed under the GPL, for accessing SquashFS filesystems.
SquashFS is intended for general read-only file system use and in constrained block device/memory systems (e.g. embedded systems) where low overhead is needed. The original version of SquashFS used gzip compression, although Linux kernel 2.6.34 added support for LZMA[1] and LZO compression,[2] Linux kernel 2.6.38 added support for LZMA2 compression (which is used by xz),[3] and Linux kernel 3.19 added support for LZ4 compression.[4]
Linux kernel 2.6.35 added support for extended file attributes.[5]
Contents
Uses
SquashFS is used by the Live CD versions of Arch Linux, Debian, Fedora, Gentoo Linux, Linux Mint, Salix, Ubuntu and on embedded distributions such as the OpenWrt[6] and DD-WRT router firmware. It is also used in Chromecast.[7] It is often combined with a union mount filesystem, such as UnionFS, OverlayFS, or aufs, to provide a read-write environment for live Linux distributions. This takes advantage of both the SquashFS's high speed compression abilities and the ability to alter the distribution while running it from a live CD. Distributions such as Debian Live, Mandriva One, Puppy Linux, Salix Live and Slax use this combination.
The on-disk format of SquashFS has stabilized enough that it has been merged into the 2.6.29 version of the Linux kernel.[8] In that process, the backward-compatibility code for older formats was removed.
SquashFS is also used by Linux Terminal Server Project and Splashtop. The tools unsquashfs and mksquashfs have been ported to Windows NT[9] - Windows 8.1.[10] 7-Zip also supports SquashFS.[11]
See also
References
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External links
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- ↑ Merge of LZ4 Squashfs support to Linus Torvalds tree.
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- ↑ http://blog.gtvhacker.com/2013/chromecast-exploiting-the-newest-device-by-google/
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- ↑ http://www.7-zip.org/