# BetrFS > file system **Wikidata**: [Q118113371](https://www.wikidata.org/wiki/Q118113371) **Source**: https://4ort.xyz/entity/betrfs ## Summary BetrFS is a file system, also known as the Bε-tree File System, that serves as a concrete format for storing files and directories on a data storage device. It functions as an operating system component to manage data retrieval and organization, abstracting physical storage into a logical hierarchy. The system is distributed under the GNU General Public License version 2.0, with source code available on GitHub. ## Key Facts - **Classification:** BetrFS is an instance of a file system, which is an operating system component and a subclass of disk storage format. - **Alias:** It is also referred to by the name Bε-tree File System. - **License:** The software is licensed under the GNU General Public License, version 2.0. - **Source Code:** The source code repository is hosted at https://github.com/oscarlab/betrfs. - **Official Website:** Information about the project is available at https://www.betrfs.org. - **Academic Documentation:** The system is described in a publication available at https://dl.acm.org/doi/10.1145/3492321.3519571. - **Copyright Status:** BetrFS holds a copyrighted status. - **Function:** As a file system, it provides a concrete format for organizing files and directories on a storage device, distinct from a virtual file system or a volume. ## FAQs ### Q: What is BetrFS? A: BetrFS is a file system, which is a concrete program or format used by an operating system to control how data is stored and retrieved on a storage device. ### Q: What license is BetrFS released under? A: BetrFS is released under the GNU General Public License, version 2.0, making it free software that allows users to run, study, share, and modify the code. ### Q: Where can I find the source code for BetrFS? A: The source code for BetrFS is publicly available in a repository on GitHub at the URL https://github.com/oscarlab/betrfs. ### Q: How does BetrFS differ from a virtual file system? A: BetrFS is a concrete file system that manages data on a physical device, whereas a virtual file system is an abstraction layer that provides a consistent interface for accessing different types of concrete file systems. ## Why It Matters BetrFS matters because it provides a specific implementation of a file system, a fundamental component required for any operating system to manage persistent data. By offering a concrete format for storing files and directories, it enables the translation of physical bit placement into a logical, hierarchical structure that users and applications can navigate. Without such a system, data placed on a storage medium would be a large, unusable body of information. Its availability under the GNU General Public License version 2.0 allows developers and researchers to access, study, and modify the software, contributing to the broader evolution of storage technologies and operating system design. ## Notable For - **Bε-tree Alias:** It is distinguished by its alternate name, the Bε-tree File System. - **Open Source Licensing:** It is distributed under the GNU General Public License, version 2.0, facilitating community access and contribution. - **Academic Foundation:** The system is formally described and documented in an academic paper published by the ACM. - **GitHub Repository:** It maintains a public presence and codebase on GitHub, specifically under the oscarlab organization. ## Body ### Definition and Purpose BetrFS is a file system, a class of software defined as a concrete format and set of programs that an operating system uses to manage files and directories on a data storage device. As an instance of an operating system component and a subclass of a disk storage format, its primary purpose is to organize data in a structured way, allowing for efficient storage, retrieval, and management. It is distinct from a virtual file system, which serves as an abstraction layer, and from a volume, which is the logical storage area a file system is applied to. BetrFS abstracts the physical details of a storage device, allowing users to work with logical files and directories without needing to know the physical location of data on the disk. ### Licensing and Distribution BetrFS is copyrighted software released under the GNU General Public License, version 2.0. This licensing model allows the software to be freely used, studied, and modified. The source code for BetrFS is maintained in a repository hosted on GitHub at https://github.com/oscarlab/betrfs. Additionally, the project maintains an official website at https://www.betrfs.org, which serves as a hub for information and resources. ### Technical Documentation The technical specifications and design of BetrFS are detailed in an academic publication. This documentation is available at the URL https://dl.acm.org/doi/10.1145/3492321.3519571, providing a formal description of the system's capabilities and architecture. The system is also known by the alias Bε-tree File System, which references its specific structural approach to data management. ### Context within File System Types While BetrFS is a specific implementation, it exists within the broader ecosystem of file system types. File systems are often categorized by design and features; while the provided text does not explicitly categorize BetrFS into specific sub-types like journaling or flash file systems, it shares the fundamental characteristic of organizing files in a hierarchical structure. Other specialized types in this field include journaling file systems (which log changes for crash recovery), log-structured file systems (which write modifications sequentially), and network file systems (which allow access over a network). BetrFS fits into this landscape as a concrete solution for the essential problem of data organization. ### Historical and Comparative Landscape The file system class includes many specialized implementations. Historical examples include the extended file system (ext) released in April 1992 and Apple's Hierarchical File System (HFS) introduced in 1985. Other variants include the Smart File System (SFS) for Amiga, the Encrypting File System (EFS) for Windows, and network or clustered systems like CXFS. BetrFS stands alongside these as a distinct file system implementation, contributing to the diverse options available for managing data storage across different computing environments. ## References 1. [Source](https://github.com/oscarlab/betrfs/blob/master/COPYING)