Page 59 - RHEL8 BOOK

BOOT PROCESS

While booting the OS crosses the 4 levels are
1. Hardware boot
 BIOS initialization
 Performs first post (power on self test)
 If all H/W connectivity are correct give healthy beep
 Boot strap find’s the device from where to boot:-
Floopy, cd-rom, hard disk.

2. Boot loader
 In linux we have default boot loader called Grub (Grand Unified BOOt Loader). In older versions
we use LILO (Linux loader)
 In this stage it reads the file “/boot/grub/grub.conf” and identifies the kernel and initrd images
which are next in the process of booting.

3. Kernel
 Kernel initializes the devices
 It mounts the root file system /
 It starts the first process “init” process (/sbin/init)
 In this stage it reads the file “/etc/fstab”

4. Init process
 init reads “/etc/inittab”
 This file contains what programmes or services should be run at different level

S. Pradhan
(MCA, MBA-IT, BCA, CCNA, MCSA 2012, RHCE, ETHICAL HACKING)
Email Id:-spradhan.iiht@gmail.com
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