The first step of the Linux boot process really has nothing whatever to do with Linux. This is the hardware portion of the boot process and is the same for any operating system. When power is first applied to the computer it runs the POST (Power On Self Test) which is part of the BIOS (Basic I/O System).
What is the first process created when booting?
When you first turn on your computer, the BIOS first performs some integrity checks of the HDD or SSD. Then, the BIOS searches for, loads, and executes the boot loader program, which can be found in the Master Boot Record (MBR).
What are the main steps to start boot a Linux system?
6 Stages of Linux Boot Process (Startup Sequence)
- BIOS. BIOS stands for Basic Input/Output System. …
- MBR. MBR stands for Master Boot Record. …
- GRUB. GRUB stands for Grand Unified Bootloader. …
- Kernel. Mounts the root file system as specified in the “root=” in grub.conf. …
- Init. …
- Runlevel programs.
What are the four steps of the Linux boot and startup process?
The booting process takes the following 4 steps that we will discuss in greater detail:
- BIOS Integrity check (POST)
- Loading of the Boot loader (GRUB2)
- Kernel initialization.
- Starting systemd, the parent of all processes.
What is the process in Linux?
In Linux, a process is any active (running) instance of a program. But what is a program? Well, technically, a program is any executable file held in storage on your machine. Anytime you run a program, you have created a process.
What are the steps of booting process?
We can describe the boot process in six steps:
- The Startup. It is the first step that involves switching the power ON. …
- BIOS: Power On Self Test. It is an initial test performed by the BIOS. …
- Loading of OS. …
- System Configuration. …
- Loading System Utilities. …
- User Authentication.
What is the difference between init 0 and shutdown?
Basically init 0 change the current run level to run level 0. shutdown -h can run by any user but init 0 can only run by superuser. Essentially the end result is the same but shutdown allows useful options which on a multiuser system creates less enemies 
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What is Initramfs in Linux?
initramfs is the solution introduced for the 2.6 Linux kernel series. … This means that firmware files are available before in-kernel drivers load. The userspace init is called instead of prepare_namespace. All finding of the root device, and md setup happens in userspace.
Does Linux use BIOS?
The Linux kernel directly drives the hardware and does not use the BIOS. … A standalone program can be an operating system kernel like Linux, but most standalone programs are hardware diagnostics or boot loaders (e.g., Memtest86, Etherboot and RedBoot).
What is run level in Linux?
A runlevel is an operating state on a Unix and Unix-based operating system that is preset on the Linux-based system. Runlevels are numbered from zero to six. Runlevels determine which programs can execute after the OS boots up.