What is the point of the 'operator' user?

Question

Many un*x systems ship with a user account named 'operator'. What is the purpose of this account?

Do some systems actually make use of this account, or is this more of a historical legacy? Have you ever made use of this account in your organization?

The 'operator' account tends have a home directory set to something like /root or /. Why is this?

Linux:

Login: operator                         Name: operator
Directory: /root                        Shell: /sbin/nologin

Or FreeBSD:

Login: operator                         Name: System Operator
Directory: /                            Shell: /usr/sbin/nologin

On FreeBSD, some files are actually owned by user 'operator':

# find / -user operator -exec ls -ld {} \;
drwx------  2 operator  operator  512 Apr 20 17:11 /var/db/entropy

This question is surprisingly hard to google, since nearly all google results are regarding shell or code operators.

Answer 1

The concept of operators origins from the second generation of computers. Back at that time, programmers used to write code on punch cards, then deliver the cards to an operator - professional staff with access to the insanely expensive mainframe machine. The operator was responsible for putting the cards on the machine for execution. When the execution was done, the operator would collect the output and the cards and deliver them back to the programmer.

During the third generation, when the first UNIXes appeared, the need for the original operators was eliminated, since time-sharing has already been introduced and programmers could write code using their own dumb terminals. Thus I will agree with Gerald and Matt that the user operator on UNIX systems was meant for doing low privileged administrative tasks (replacing tapes, backups, maintenance, etc.).

Answer 2

Matt's answer is quite correct but misses the historical context that when UNIX systems were first brought into larger data centers "operator" was usually the actual job title for the staff performing simple routine tasks on the systems.

Answer 3

The operator user was traditionally there for simple maintenance, so usually has unrestricted read access to disks (by also being in the operator group) to perform dumps / backups. That way a backup can be taken without requiring root pw.