AUTOEXEC.BAT is a file containing Disk Operating System commands that are executable when the computer is booted (started). The commands in AUTOEXEC.BAT tell the operating system which application programs are to be automatically started, how memory is to be managed, and initialize other settings. Each command in AUTOEXEC.BAT could be typed in manually after the computer is started, but that would take too long. The AUTOEXEC.BAT file is, in fact, a command script that is written beforehand so that it can be automatically executed when the operating system is started. The BAT suffix stands for batch, indicating that this is a file containing a sequence of commands entered from a file rather than interactively by a user.