Boot Loader Overview

• GRUB – A near-universal normal on Linux systems, with BIOS/MBR and UEFI versions.
• LILO – One of the primary Linux bootloaders. ELILO could be a UEFI version.
• SYSLINUX – It may be organized to run from many alternative styles of filesystems.
• LOADLIN – Boots a kernel from DOS.
• System-boot a straightforward UEFI boot manager.
• coreboot – A superior replacement for the computer BIOS which will embody a kernel.
• Linux Kernel EFISTUB A kernel plug-in for loading the kernel directly from associate EFI/UEFI System Partition.
• EFI Linux – A UEFI boot loader meant to function as a model and reference for different UEFI boot loaders.

Introduction and Work of Few Bootloaders mentioned above:

1) GRUB:   

GRUB stands for Grand Unified Boot Loader. One of GRUB’s most vital capabilities is filesystem navigation that enables straightforward kernel image and configuration choice.

• Upon finding the boot code, the BIOS hundreds and executes it. This is often wherever GRUB begins.
• The GRUB core hundreds.
• The core initializes. At now, GRUB will currently access disks and filesystems.
• GRUB identifies its boot partition and hundreds of configurations there.
• GRUB offers the user an opportunity to vary the configuration.
• GRUB executes the configuration after a timeout or user action.
• In the course of execution of the configuration, GRUB might load further code within the boot partition. a number of these modules are also preloaded.
• To load and execute the kernel GRUB executes boot commands.

2) LILO (LInux LOader):

It was the first bootloader developed for Linux, still some users use it today. If we compare it to the GRUB bootloader it is quite simple and primarily used with BIOS system. To install it on Linux system one can install it using package manager like apt or yum. After installation it can be easily configured by editing its configuration file located at `/etc/lolo.conf`.

3) SYSLINUX:

It is lightest among other bootloaders; it can perform booting from removable media such as CDs or USB drives. Its key feature is that it supports different filesystems, a command-line interface and the ability to boot from multiple devices.  For example, to install SYSLINUX on a USB drive we can configure SYSLINUX setting by editing its configuration file located in `/syslinux/syslinux.cfg`.

Many processes are running in the background when we press the system’s power button. It is very important to learn the booting process to understand the working of any operating system. Knowing how the kernel boots is a must to solve the booting error. It is a very interesting topic to learn, let us start with the basics. A simplified read of the boot method is given below: