How to Use MS-DOS 6.22 Step-by-Step Boot with F8

In MS-DOS 6.22, the feature that enables users to single-step through configuration files is known as Interactive Boot, or Step-by-Step Confirmation. This troubleshooting utility gives users granular control over system startup by allowing them to selectively execute or bypass individual commands in both CONFIG.SYS and AUTOEXEC.BAT. This article outlines how the feature functions, how to initiate it using the F8 key, and how to use it to isolate driver errors and hardware conflicts.

What is Interactive Boot?

Interactive Boot is a diagnostic startup mode designed to resolve boot failures caused by corrupted drivers, conflicting terminate-and-stay-resident (TSR) programs, or improper memory configuration settings. When invoked, MS-DOS temporarily halts its automated startup procedure and prompts the user for confirmation before executing each directive.

How to Access the Feature

  1. Turn on or restart the computer.
  2. When the text "Starting MS-DOS..." appears on the screen, immediately press the F8 key.
  3. MS-DOS will pause its standard boot sequence and display: MS-DOS will prompt you to confirm each line of CONFIG.SYS.

Stepping Through CONFIG.SYS

Once activated, MS-DOS evaluates CONFIG.SYS one line at a time. For each directive (such as DEVICE=, DOS=HIGH, or FILES=), the system displays the exact command followed by a [Y,N]? prompt:

  • Press Y (Yes): Executes the line and loads the specified driver or setting into memory.
  • Press N (No): Skips the line entirely, leaving the driver unloaded.
  • Press Esc: Automatically executes all remaining lines in CONFIG.SYS without further prompts.
  • Press F5: Immediately bypasses all remaining startup commands, equivalent to performing a clean boot.

Stepping Through AUTOEXEC.BAT

After the last line of CONFIG.SYS is processed, MS-DOS 6.22 asks whether to process AUTOEXEC.BAT.

  • Selecting Y prompts you to confirm each command inside AUTOEXEC.BAT individually, allowing you to bypass specific TSRs, environment variables, or batch scripts.
  • Selecting N skips the file completely, dropping the system directly to the command prompt (C:\>).

Diagnostic Benefits

By selectively disabling commands, you can systematically isolate problematic drivers—such as unstable extended memory managers (HIMEM.SYS, EMM386.EXE), CD-ROM drivers, or sound card utilities—without modifying the underlying text files using a text editor. Once the offending line is identified, the system can boot cleanly to allow for permanent repair.