MS-DOS 6.22 CONFIG.SYS Num Lock Directive

This article explains how to configure the initial state of keyboard lock keys in MS-DOS 6.22 using the CONFIG.SYS system configuration file. It covers the specific directive used to set keyboard lock states at startup, the syntax required, and the operational limitations regarding other toggle keys like Caps Lock and Scroll Lock.

The NUMLOCK Directive

In MS-DOS 6.22, the configuration directive used to control keyboard lock states during boot is NUMLOCK. Introduced in MS-DOS 6.0, this command allows you to specify whether the Num Lock key state is turned on or off when the computer starts up.

Syntax and Parameters

To use the directive, add it on its own line in your C:\CONFIG.SYS file using the following syntax:

NUMLOCK=ON

or

NUMLOCK=OFF
  • ON: Turns the keyboard's Number Lock state on when the operating system boots.
  • OFF: Turns the keyboard's Number Lock state off when the operating system boots.

How to Implement the Setting

  1. Open your MS-DOS text editor by typing EDIT C:\CONFIG.SYS at the command prompt.
  2. Locate a blank line or place the command near the top of the file, outside of menu configuration blocks if you use multi-boot menus, or inside specific blocks if you require different settings per configuration.
  3. Type NUMLOCK=OFF (or NUMLOCK=ON).
  4. Save the file and exit the editor.
  5. Restart your computer to apply the change.

Handling Caps Lock and Scroll Lock

MS-DOS 6.22 does not provide native CONFIG.SYS directives for setting the default states of Caps Lock or Scroll Lock (such as CAPSLOCK= or SCROLLLOCK=). The NUMLOCK directive is the only built-in command provided for lock keys.

If you need to define the boot state for Caps Lock or Scroll Lock, you must either adjust the settings directly in your system's motherboard BIOS/UEFI setup utility (if supported) or run a custom assembly utility or terminate-and-stay-resident (TSR) program via your AUTOEXEC.BAT file to manipulate keyboard status flags in the BIOS Data Area at memory address 0040:0017.