An OS X backup utility that automatically backs up files to a dedicated drive that is always available when the computer is turned on is called .

Time machine.

Explanation:

An OS X backup utility that automatically backs up files to a dedicated drive that is always available when the computer is turned on is called a time machine.

OS X was released in 2001 and it's Apple's version ten (10) of the operating system that runs on its Macintosh computers.

A time machine is a software tool built into the Mac operating system and it is primarily designed to automatically backup user files or data onto a dedicated drive such as an external hard drive disk through a wired connection, by using a Thunderbolt or universal serial bus (USB) cable. The automatic backup can as well be done wirelessly through a network connection.