A+ Certification / Beginners

MS-DOS and Windows 9x Boot Errors

The Windows 9x and MS-DOS boot processes are identical, up until the point that the Windows 9x GUI is started with the execution of win.com. This section will look at the errors that you may encounter during the MS-DOS portion of the boot process, prior to win.com starting. In many cases, because of a need to support FAT32 or large disks, many people use a Windows 98 boot disk instead of an MS-DOS 6.22 boot disk.

A Windows 9x boot disk is used regularly as a rescue medium or during a pre-OS installation phase so it is extremely useful to know and be able to troubleshoot the boot process of this disk. Since I am not actually booting Windows with disk, but rather the MS-DOS command shell that ships with Windows 9x, I will be referring to this disk as an MS-DOS boot disk. Most of the problems surrounding the boot process involve the five main startup files: io.sys, msdos.sys, config.sys, autoexec.bat, and command.com. The following sections look at some of the common error messages you may receive.

Error in config.sys line XX

When working with an MS-DOS boot disk, your config.sys and autoexec. bat files, if they exist, are processed during startup. Depending on the settings found in your msdos.sys file, there may or may not be an animated Windows 9x logo. The purpose of the Windows 9x animated logo is to hide the processing of these two files. When processing the config.sys file, any errors in the file are reported to the screen, and the animated logo is suspended.

config.sys and autoexec.bat are required startup files for MS-DOS but are used by Windows 9x to override default settings that Windows 9x already uses or to allow backward compatibility with MS-DOS-based applications. If you do not need to override settings or provide backward compatibility, your system doesn't need these two files. For more information about these files and the Windows 9x boot process.

If you want to see all of the lines in the config.sys process, press the Esc key when you see the text "Starting Windows 9x" or anytime after the animated logo is on the screen. If you press the Esc key after the animated logo is displayed, the animated logo will show up again when the monitor's refresh rate is adjusted, so you will have to press the Esc key a second time to remove it again.

If there is a problem with the config.sys file, you may see an error message that resembles this section heading, Error in config.sys line XX. As the error message suggests, there is an error in line xx of your config.sys file. config.sys is a text file on the root of your boot drive. Because it's a text file, you can open it with any text editor, such as edit.com or notepad. exe, and change it. Count down the number of lines indicated by the error message, starting with one, to get to the offending line. This line likely has some type of syntax error. Check to make sure the path or file that is referenced by the line in config.sys matches the actual location. This error can also result from passing the wrong parameters to a program or driver.

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