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GNU GRUB | Free and open-source software

By Monika Sharma, on February 16, 2020

What Is GNU GRUB?

GNU GRUB (generally alluded to as GRUB) is a boot loader from the GNU Project. GRUB is the reference execution of the Free Software Foundation's Multiboot Specification, which gives a client the decision to boot one of different working OS introduced on a PC or select a particular kernel config accessible on a specific OS partition.

A package was extracted as GNU GRUB and called the Grand Unified Bootloader It is overwhelmingly utilized for Unix-like systems. The GNU OS utilizes GNU GRUB as its boot loader, as do most Linux distributions and the Solaris OS on x86 systems, beginning with the Solaris 10 1/06 version.

Grub (the GRand Unified Bootloader) is a boot loader intended to address the impediments of LILO. It compensates for various lacks in numerous PC BIOSs while giving full-highlighted direction line and graphical interfaces. Grub perceives Fdisk allotments, can powerfully peruse Linux ext2fs, and MSDOS FAT16 and FAT32 filesystems, and can boot multiboot-consistent pieces.

A bootloader is significant as it is difficult to begin an OS without it. It is the principal program that begins when the program is turned on. The bootloader moves the control to the OS Kernel.

GRUB Features

GRUB is the default bootloader for almost every Linux Distribution available in the market because of the feature and extensions of previous bootloaders. Some of the features of GRUB are as Follows,

• LBA (Logical Block Addressing Mode) is supported by GRUB which puts the tending to transformation used to discover documents into the firmware of the hard drive.
• GRUB gives the greatest adaptability in stacking the OS with required alternatives utilizing a direction based, pre-operating system condition.
  The booting choices, for example, kernel parameters can be altered utilizing the GRUB command line.
• There is no compelling reason to indicate the physical area of the Linux portion for GRUB. It just required the hard circle number, the parcel number and record name of the piece.
• GRUB can boot practically any OS utilizing the direct and chain stacking boot techniques.

GRUB Installation Process

After installation GRUB becomes the default bootloader automatically, only the steps to install GRUB should be kept in mind,

1. Make sure you use the latest version of the GRUB package and install the same.
2. The root shell prompt opens up and the command "/sbin/grub-install" must be run as soon as the GRUB package is installed on the system. You will see in the command the installed location of GRUB Stage 1 Bootloader.
3. As soon as you follow these steps, restart your system.
4. GRUB graphical bootloader menu appears before any of the OS Kernels is loaded onto memory as soon as your system boots up.

GRUB Interfaces

There are three interfaces in GRUB which all give various degrees of usefulness. The Linux kernel can be booted by the users with the assistance of these interfaces. Insights concerning the interfaces are,

1. Menu Interface: The GRUB is arranged by the installation program in the menu interface. It is the default interface accessible. It contains a list of the OS or kernels which are requested by name. An OS or kernel can be chosen utilizing the navigation keys and it very well may be booted utilizing the enter key.
2. Menu Entry Editor Interface: The key in the boot loader menu is utilized to get to the menu section proofreader. All the GRUB commands for the specific menu section are shown there and these directions might be modified before stacking the OS.
3. Direction Line Interface: This interface is the most fundamental GRUB interface yet it gives the most control to the client. Utilizing the command line interface, any order can be executed by composing it and afterward pressing enter. This interface likewise includes some propelled shell features.