# Fossil

> file system in Plan 9

**Wikidata**: [Q11681908](https://www.wikidata.org/wiki/Q11681908)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Fossil_(file_system))  
**Source**: https://4ort.xyz/entity/fossil

## Summary
Fossil is the default file system for the Plan 9 operating system. It is designed as an archival file server, responsible for storing files and directories. Fossil uses the 9P protocol for all file access and communication.

## Key Facts
- **Instance of:** File system
- **Operating System:** Plan 9
- **Protocol:** Uses the 9P protocol
- **Primary Function:** Described as an archival file server
- **Documentation:** Detailed in the paper "Fossil, an Archival File Server"
- **Paper Authors:** Russ Cox, Sean Quinlan, and Jim McKie
- **Wikipedia Presence:** Has articles in English, Spanish, Russian, and Chinese

## FAQs
### Q: What is Fossil?
A: Fossil is the native file system used by the Plan 9 operating system. It functions as an archival file server, meaning it is designed for persistent storage of files and directories with features for data integrity and history.

### Q: What operating system uses Fossil?
A: Fossil is the file system for the Plan 9 operating system.

### Q: What protocol does Fossil use?
A: Fossil uses the 9P protocol for all file system operations. This protocol is a core component of the Plan 9 architecture, enabling network-transparent access to resources.

## Why It Matters
Fossil is significant as a key component of Plan 9, an influential research operating system that pioneered concepts like network transparency and representing all system resources as files. Fossil embodies this philosophy by using the 9P protocol to serve files, making local and remote storage access seamless. Its design as an "archival file server" highlights a focus on data integrity and versioning, features that were not standard in many contemporary file systems. By integrating these archival capabilities directly into the main file server, Fossil provided a robust and simplified solution for data snapshots and history, influencing later designs in distributed and versioning file systems. Its existence and documentation provide a clear example of an alternative approach to file system architecture, distinct from the models used in more mainstream operating systems.

## Notable For
- **Plan 9 Integration:** Fossil is the default, native file system for the Plan 9 operating system.
- **Archival Design:** It is explicitly designed as an archival file server, a core part of its identity and function.
- **9P Protocol Usage:** It exclusively uses the 9P protocol, which is central to Plan 9's "everything is a file" and network-centric design.
- **Formal Documentation:** The file system's architecture is formally described in the academic paper "Fossil, an Archival File Server" by Russ Cox, Sean Quinlan, and Jim McKie.

## Body
### Core Functionality
Fossil is an instance of a file system, providing a concrete format for storing files and directories on a data storage device. Its primary role is to act as an archival file server.

### System Integration
Fossil is the file system for the Plan 9 operating system. It is the default and primary storage system used within that environment.

### Protocol
Fossil uses the 9P protocol for all of its operations. This protocol facilitates communication and data transfer between the file server and other parts of the system, enabling Plan 9's characteristic network transparency.

### Documentation
The design and implementation of Fossil are detailed in a paper titled "Fossil, an Archival File Server." The authors of this English-language paper are listed as Russ Cox and Sean Quinlan, with Jim McKie also credited.