MS-DOS 6.22 System Initialization Script File Suffix

This article identifies the file extension used for system initialization scripts in MS-DOS 6.22, detailing the specific role of the .BAT format during the boot process, how the primary startup script functions, and how it differs from low-level configuration files.

In MS-DOS 6.22 setups, the file suffix that denotes system initialization scripts is .BAT, short for "batch." Batch files are plain text files containing sequences of commands that the command interpreter executes sequentially.

The primary system initialization script in MS-DOS 6.22 is AUTOEXEC.BAT. Located in the root directory of the boot drive (typically C:\), this file is automatically executed by the command interpreter (COMMAND.COM) at the final stage of the boot sequence.

The purpose of AUTOEXEC.BAT is to automate user-level initialization tasks. Common functions include:

• Setting global environment variables, such as PATH, TEMP, and PROMPT.
• Loading Terminate-and-Stay-Resident (TSR) programs, such as mouse drivers, keymaps, or MSCDEX (Microsoft CD-ROM Extensions).
• Running utility programs, such as disk caches (SMARTDrive) or anti-virus monitors.
• Launching a primary user interface, shell, or menu system immediately after startup.

While MS-DOS 6.22 also relies on CONFIG.SYS during boot, that file uses the .SYS extension and is not an executable script. Instead, CONFIG.SYS is a static configuration file processed directly by the DOS kernel (MSDOS.SYS / IO.SYS) to configure memory management, specify system buffers, and load low-level device drivers before the command interpreter and AUTOEXEC.BAT run. Consequently, .BAT remains the definitive suffix for actual executable initialization scripts in MS-DOS.