A privilege bit that allows the possessor to perform some

restricted operation on a time-sharing system, such as read

or write any file on the system regardless of protections,

change or look at any address in the running monitor, crash or

reload the system, and kill or create jobs and user accounts.

The term was invented on the TENEX operating system, and

carried over to TOPS-20, XEROX-IFS, and others. The state of

being in a privileged logon is sometimes called "wheel mode".

This term entered the Unix culture from TWENEX in the

mid-1980s and has been gaining popularity there (especially at

university sites). See also root.