Fossil is the default
file system in
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 ...
. It serves the network protocol
9P and runs as a
user space
A modern computer operating system usually uses virtual memory to provide separate address spaces or regions of a single address space, called user space and kernel space. This separation primarily provides memory protection and hardware prote ...
daemon
A demon is a malevolent supernatural being, evil spirit or fiend in religion, occultism, literature, fiction, mythology and folklore.
Demon, daemon or dæmon may also refer to:
Entertainment Fictional entities
* Daemon (G.I. Joe), a character ...
, like most Plan 9 file servers. Fossil is different from most other file systems due to its
snapshot/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 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 may refer to:
* Venti (software), a network storage system
* Venti, a character in 2020 video game '' Genshin Impact''
*A coffee cup size at Starbucks
*The Roman equivalent of the Greek Anemoi
In ancient Greek religion and Greek mytho ...
. 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 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 Porting, 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, Fr ...
.
History
Fossil was designed and implemented by Sean Quinlan,
Jim McKie and
Russ Cox at
Bell Labs
Nokia Bell Labs, commonly referred to as ''Bell Labs'', is an American industrial research and development company owned by Finnish technology company Nokia. With headquarters located in Murray Hill, New Jersey, Murray Hill, New Jersey, the compa ...
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 bilateria, bilateral animals that typically have a long cylindrical tube-like body, no limb (anatomy), limbs, and usually no eyes.
Worms vary in size from microscopic to over in length for marine ...
optical disc system. The permanent storage for fossil is provided by
Venti
Venti may refer to:
* Venti (software), a network storage system
* Venti, a character in 2020 video game '' Genshin Impact''
*A coffee cup size at Starbucks
*The Roman equivalent of the Greek Anemoi
In ancient Greek religion and Greek mytho ...
, which typically stores data on hard drives, which have much lower access times than optical discs.
References
See also
*
GoogleFS – Google's proprietary distributed filesystem
External links
* .
* .
{{File systems
2002 software
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 preserve ...
Plan 9 from Bell Labs