Learning Linux Shell Scripting - Second Edition

The kernel startup and init process

In our computers, there is one EPROM chip called the BIOS, which is situated on the motherboard or main board of our computers. When we power-on, the processor starts executing a program from the BIOS. The program in the BIOS does a power-on-self-test, checking memory and other peripherals. Then the BIOS program initializes the basic hardware required for PC operation, such as initializing the PCI bus, video devices, and similar.

Finally, the BIOS checks the boot device sequence and queries the first boot device. This BIOS program then reads the master boot record of the first boot device, which is normally a hard disk, USB device, or DVD. Once the BIOS reads the master boot record of the first boot device, ...