Objective 2: Identifying Boot Stages

Chapter 14 covered the boot process of a Linux system. This section discusses how to identify which step of the boot process has caused a problem.

Typically, a failure at any given stage of the boot process looks like the following:

Failure to read and load the boot sector

A failure at this stage occurs after the BIOS screen disappears and before any part of the operating system is run. A failure here means that the boot sector was not found or did not load. Typically, you will see a blank screen with just a flashing prompt or a message similar to "No operating system found.". Possible problems include:

  • The boot sector is trashed and must be reinstalled.

  • The partition listed as the active partition has no boot sector.

  • The wrong partition has been marked as "active."

Failure to load the boot loader

What you see will depend on which boot loader you have.

If you're using LILO, the LILO prompt itself will lead you to the problem (see the next section). If you're using GRUB, an error may appear, followed by the initial GRUB screen.

Failure to load the kernel

This can have several causes, including a bad hard drive sector, inability to find a particular kernel module, or inability to find the root device. Typically, any of these errors will result in a "kernel panic." At this point, you need to review the on-screen data to determine where the problem lies.

Failure to run the init daemon and enter a specific run level

If you get past the kernel load, the ...

Get LPI Linux Certification in a Nutshell, 2nd Edition now with the O’Reilly learning platform.

O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.