In this chapter, you learned about the Linux boot process. The basic process starts with the computer BIOS. Once it detects basic hardware on your system, it points to the Linux bootloader (GRUB), where you can select an operating system. When you select Red Hat Linux, the bootloader starts the kernel. The /etc/inittab file then starts the processes associated with the default runlevel.
It helps to have the customized boot disk that you created during Linux installation or with the mkbootdisk command. It can help you start Linux even when you have a number of different problems in the boot process. However, linux rescue mode, using one of the Red Hat Linux installation boot disks, is also a viable option. In various linux rescue modes, you can fsck partitions, edit configuration files, and more. Alternatively, you can start Linux in single- user mode, which can help you address other problems, such as a lost root password.
In Red Hat parlance, it s common to refer to a partition check by its command, i.e., you can fsck (pronounced "fisk") a partition.
In the next chapter , you will learn about the Linux kernel in detail. Once you understand the basics, it is not difficult to modify, recompile, and implement a new Linux kernel.