Fossil is the default

file system In computing, file system or filesystem (often abbreviated to fs) is a method and data structure that the operating system uses to control how data is stored and retrieved. Without a file system, data placed in a storage medium would be one larg ...

Plan 9 from Bell Labs Plan 9 from Bell Labs is a distributed operating system which originated from the Computing Science Research Center (CSRC) at Bell Labs in the mid-1980s and built on UNIX concepts first developed there in the late 1960s. Since 2000, Plan 9 has be ...

. It serves the network protocol 9P and runs as a

user space A modern computer operating system usually segregates virtual memory into user space and kernel space. Primarily, this separation serves to provide memory protection and hardware protection from malicious or errant software behaviour. Kernel ...

daemon Daimon or Daemon (Ancient Greek: , "god", "godlike", "power", "fate") originally referred to a lesser deity or guiding spirit such as the daimons of ancient Greek religion and Greek mythology, mythology and of later Hellenistic religion and Hell ...

, like most Plan 9 file servers. Fossil is different from most other file systems due to its

snapshot Snapshot, snapshots or snap shot may refer to: * Snapshot (photography), a photograph taken without preparation Computing * Snapshot (computer storage), the state of a system at a particular point in time * Snapshot (file format) or SNP, a file ...

/archival feature. It can take snapshots of the entire file system on command or automatically (at a user-set interval). These snapshots can be kept on the Fossil

partition Partition may refer to: Computing Hardware * Disk partitioning, the division of a hard disk drive * Memory partition, a subdivision of a computer's memory, usually for use by a single job Software * Partition (database), the division of a ...

as long as disk space allows; if the partition fills up then old snapshots will be removed to free up disk space. A snapshot can also be saved permanently to

Venti Venti is a network storage system that permanently stores data blocks. A 160-bit SHA-1 hash of the data (called ''score'' by Venti) acts as the address of the data. This enforces a ''write-once'' policy since no other data block can be found wi ...

. Fossil and Venti are typically installed together.

Features

Important features include: *Snapshots are available to all users. No administrator intervention is needed to access old data. (This is possible because Fossil enforces file permissions; users can only access data which they would be allowed to access anyway; thus a user cannot snoop on another's old files or look at old passwords or such.) *Data in permanent snapshots (sometimes called archives) cannot be modified. Only the non-permanent snapshots can be removed. To access a snapshot, one would connect to a running fossil instance (“mount” it) and change directory to the desired snapshot, e.g. ''/snapshot/yyyy/mmdd/hhmm'' (with ''yyyy'', ''mm'', ''dd'', ''hh'', ''mm'' meaning year, month, day, hour, minute). To access an archive (permanent snapshot), a

directory Directory may refer to: * Directory (computing), or folder, a file system structure in which to store computer files * Directory (OpenVMS command) * Directory service, a software application for organizing information about a computer network's u ...

of the form ''/archive/yyyy/mmdds'' (with ''yyyy'', ''mm'', ''dd'', ''s'' meaning year, month, day, sequence number) would be used. Plan 9 allows modifying the

namespace In computing, a namespace is a set of signs (''names'') that are used to identify and refer to objects of various kinds. A namespace ensures that all of a given set of objects have unique names so that they can be easily identified. Namespaces ...

in advanced ways, like ''redirecting'' one path to another path (e.g. ''/bin/ls'' to ''/archive/2005/1012/bin/ls''). This significantly eases working with old versions of files. Fossil is available on several other platforms via

Plan 9 from User Space Plan 9 from User Space (also plan9port or p9p) is a port of many Plan 9 from Bell Labs libraries and applications to Unix-like operating systems. Currently it has been tested on a variety of operating systems including: Linux, macOS, FreeBSD, Net ...

History

Fossil was designed and implemented by Sean Quinlan,

Jim McKie Jim or JIM may refer to: * Jim (given name), a given name * Jim, a diminutive form of the given name James * Jim, a short form of the given name Jimmy * OPCW-UN Joint Investigative Mechanism * ''Jim'' (comics), a series by Jim Woodring * ''Jim' ...

and

Russ Cox Russ is a masculine given name, often a short form of Russell, and also a surname. People Given name or nickname * Russ Abbot (born 1947), British musician, comedian and actor * Russ Adams (born 1980), American retired baseball player * Russ B ...

Bell Labs Nokia Bell Labs, originally named Bell Telephone Laboratories (1925–1984), then AT&T Bell Laboratories (1984–1996) and Bell Labs Innovations (1996–2007), is an American industrial research and scientific development company owned by mult ...

and added to the Plan 9 distribution at the end of 2002. It became the default file system in 2003, replacing Kfs and the previous Plan 9 archival file system, dubbed ''The Plan 9 File Server'', or " fs". fs is also an archival file system which originally was designed to store data on a

WORM Worms are many different distantly related bilateral animals that typically have a long cylindrical tube-like body, no limbs, and no eyes (though not always). Worms vary in size from microscopic to over in length for marine polychaete wor ...

optical disc system. The permanent storage for fossil is provided by

, which typically stores data on hard drives, which have much lower access times than optical discs.

External links

* . * . * , about data structures written to venti {{File systems

Fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

Plan 9 from Bell Labs

Features

History

See also

External links