Root directory
In acomputerfile system,and primarily used in theUnixandUnix-likeoperating systems,theroot directoryis the first or top-mostdirectoryin a hierarchy.[1]It can be likened to the trunk of atree,as the starting point where all branches originate from. Theroot file systemis the file system contained on the samedisk partitionon which the root directory is located; it is the filesystem on top of which all other file systems aremountedas the system boots up.[2]
Unix-like systems
[edit]Unix abstracts the nature of this tree hierarchy entirely and in Unix and Unix-like systems the root directory is denoted by the/(slash) sign. Though the root directory is conventionally referred to as/,the directory entry itself has no name – its path is the "empty" part before the initial directory separator character (/). All file system entries, including mounted file systems are "branches" of this root.[1]
chroot
[edit]In UNIX-like operating systems, eachprocesshas its own idea of what the root directory is. For most processes this is the same as the system's actual root directory, but it can be changed by calling thechrootsystem call.This is typically done to create a secluded environment to run software that requires legacy libraries and sometimes to simplify software installation and debugging. Chroot is not meant to be used for enhanced security as the processes inside can break out.[3]
Super-root
[edit]Some Unix systems support a directory below the root directory. Normally, "/.." points back to the sameinodeas "/", however, underMUNIX,this can be changed to point to a super-root directory, where remote trees can be mounted.[4][5]If, for example, two workstations "pcs2a" and "pcs2b" were connected via "connectnodes" and "uunite" startup script, "/../pcs2b" could be used to access the root directory of "pcs2b" from "pcs2a".
DOS/Windows systems
[edit]UnderDOS,OS/2,andMicrosoft Windows,each partition has a drive letter assignment (e.g. the C partition is labeledC:\) and there is no public root directory on it.
Related uses
[edit]On manyUnixes,there is also a directory named/root(pronounced "slash root" ).[6]This is thehome directoryof the 'root'superuser.On manyMacandiOSsystems this superuser home directory is/var/root.[6]
See also
[edit]References
[edit]- ^ab"Root Directory Definition".techterms.Archivedfrom the original on 2020-10-26.Retrieved2020-03-14.
- ^"Root Filesystem Definition by The Linux Information Project".LInfo.org.Archivedfrom the original on 2021-07-10.Retrieved2020-03-14.
- ^"What chroot() is really for".LWN.net.Archivedfrom the original on 2020-11-12.Retrieved2014-02-12.
- ^Brownbridge, David R.; Marshall, Lindsay F.;Randell, Brian(1982)."The Newcastle Connection"(PDF).Software: Practice and Experience.12:1147–1162.doi:10.1002/spe.4380121206.S2CID1840438.Archived fromthe original(PDF)on 2016-08-16.Retrieved2016-08-16.
- ^Callaghan, Brent (2000).NFS Illustrated.Addison Wesley.ISBN0-201-32570-5.
- ^ab"Root Definition".LInfo.org.The Linux Information Project. 2007-10-27.Archivedfrom the original on 2021-05-08.Retrieved2021-11-03.
