# SquashFS

> compressed, read-only file system for Linux

**Wikidata**: [Q389314](https://www.wikidata.org/wiki/Q389314)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/SquashFS)  
**Source**: https://4ort.xyz/entity/squashfs

## Summary
SquashFS is a compressed, read-only file system designed for Linux. It allows for efficient storage and distribution of files and directories, making it suitable for environments where space is limited and data integrity is crucial.

## Key Facts
- SquashFS is a compressed, read-only file system for Linux.
- It is licensed under the GNU General Public License, version 2.0 or later.
- The developers include Robert Lougher and Phillip Lougher.
- A patch for SquashFS was conceived on October 23, 2002.
- SquashFS was integrated into the Linux kernel version 2.6.29 in 2009.
- It is classified as a file system, free software, and an archive file format.
- SquashFS supports both big-endian and little-endian SquashSF image file formats.
- Its primary programming language is identified as Q15777.

## FAQs
### Q: What is SquashFS?
A: SquashFS is a compressed, read-only file system specifically designed for Linux. It enables efficient storage and distribution of files and directories, particularly useful in scenarios requiring data integrity and minimal storage footprint.

### Q: Who developed SquashFS?
A: SquashFS was developed by Robert Lougher and Phillip Lougher.

### Q: What operating systems does SquashFS support?
A: SquashFS is designed for and primarily supported on the Linux operating system.

### Q: What is the license for SquashFS?
A: SquashFS is distributed under the GNU General Public License, version 2.0 or later.

### Q: When was SquashFS first introduced or integrated?
A: A patch for SquashFS was conceived on October 23, 2002. It was later integrated into the Linux kernel starting with version 2.6.29 in 2009.

## Why It Matters
SquashFS plays a significant role in various Linux-based systems due to its unique combination of compression and read-only characteristics. Its ability to create highly compressed file systems is crucial for embedded devices, live CDs/DVDs, and system recovery environments where storage space is often limited. The read-only nature ensures that the file system remains immutable, providing enhanced data integrity and security against accidental or malicious modifications. This makes it an ideal choice for distributing software, operating system images, or any data that needs to be accessed reliably without alteration. Its integration into the Linux kernel as a native file system further solidifies its importance as a robust and widely adopted solution for efficient and secure data packaging.

## Notable For
- Being a compressed, read-only file system, optimizing storage and ensuring data immutability.
- Its native integration into the Linux kernel since version 2.6.29.
- Its widespread use in embedded systems, live Linux distributions, and system recovery tools.
- Being free and open-source software, licensed under the GNU General Public License.

## Body

### Overview
SquashFS is a specialized file system for Linux, characterized by its compressed and read-only nature. It functions as a concrete format or program for storing files and directories on a data storage device, providing an efficient way to package and distribute data.

### Development and History
SquashFS was developed by Robert Lougher and Phillip Lougher. The initial concept, in the form of a patch, dates back to October 23, 2002. It was subsequently integrated into the main Linux kernel, becoming part of kernel version 2.6.29 in 2009.

### Technical Specifications
- **License**: SquashFS is distributed under the GNU General Public License, version 2.0 or later.
- **Operating System Support**: It is designed for and primarily operates on Linux.
- **File Formats**: SquashFS supports its own image file formats, specifically SquashSF image file (big endian) and SquashSF image file (little endian). These formats are both readable and writable in terms of creating the image.
- **Programming Language**: The programming language used is identified as Q15777.
- **Copyright Status**: SquashFS is copyrighted.

### Classification and Related Concepts
SquashFS is categorized as:
- A file system.
- Free software.
- An archive file format.

### Resources
- **Official Website**: https://github.com/plougher/squashfs-tools
- **Source Code Repository**: git://git.kernel.org/pub/scm/fs/squashfs
- **Documentation**: Described at URLs such as `https://www.sweetscape.com/010editor/repository/files/SquashFS.bt` (010 Editor Binary Template) and `https://github.com/AgentD/squashfs-tools-ng/blob/master/doc/format.txt`.
- **Wikipedia**: An entry exists under the title "SquashFS", with articles available in multiple languages including Arabic, Czech, German, English, Spanish, French, Italian, Japanese, Korean, and Dutch.
- **Gentoo Wiki**: Articles are available, including "SquashFS" (English), "SquashFS/hu" (Hungarian), and "SquashFS/ja" (Japanese).

## References

1. [README](https://sourceforge.net/projects/squashfs/files/squashfs/squashfs4.3/)
2. [The squashfs Open Source Project on Open Hub: Licenses Page. Open Hub](https://www.openhub.net/p/squashfs/licenses)
3. [Source](https://sourceforge.net/projects/squashfs/files/squashfs/squashfs4.3/squashfs4.3.tar.gz/download)
4. [The squashfs Open Source Project on Open Hub: Languages Page. Open Hub](https://www.openhub.net/p/squashfs/analyses/latest/languages_summary)
5. Freebase Data Dumps. 2013