Original subtitles

computers use firmware to initialize

Hardware firmware is a small program

stored inside a chip on the motherboard

when we start a computer it is the first

program that the computer runs it

performs three tasks initialize all

Hardware devices find the bootloader

program and execute it in the first step

it checks whether all Hardware devices

are functional if yes it moves to the

Second Step if not it halts the startup

process this process is known as power

on cell test or post in the second step

it finds the bootloader program we can

store a bootloader program on any

external storage device such as a hard

disk USB drive CD or a DVD all OS

installation discs come with a

bootloader program the installation

program transfers it to the hard disk

when we install the operating system

firmware allows us to specify the boot

device priority the boot device priority

defines the boot order firmware checks

the specified devices in a sequence

until it finds a bootloader program once

it finds a bootloader program it does

not check the next device in the

sequence let us take an example suppose

three devices hard disk DVD ROM and USB

drive are configured in the boot device

Priority First firmware will find the

bootloader program on the hard disk if

it finds a bootloader program on the

hard disk it executes it and does not

check the CD ROM and USB drive if it

does not find a bootloader program on

the hard disk it checks the DVD ROM if

the DVD ROM has a disc it finds the boot

loader program on it if the DVD ROM does

not have a DVD or has a non- bootable

DVD the firmware checks all USB ports

for a connected USB drive if a USB drive

is attached the firmware finds the

bootloader program on it if firmware

does not find a bootloader program on

any specified device it halts the boot

process if it finds a bootloader program

on any specified device it executes the

bootloader program the boot boot loader

program controls the remaining boot

process there are two types of firmware

bios and UA both find the boot loader

program on different regions of the

specified devices in the boot device

list bios finds it on the first sector

of the specified devices it reads the

first 512 bytes of the device it calls

them MBR if the MBR contains a

bootloader program it executes the

program if it does not contain a

bootloader program it finds a bootloader

program on the MBR of the next speci

specified device in the boot device list

UA finds a bootloader after the first

sector it reads 4 kilobytes after

skipping the first 512 bytes it calls

them GPT if the GPT contains a

bootloader program it executes the

program if it does not contain the

bootloader program it checks the GPT of

the next specified device in the boot

device

list bios is a classical method to save

firmware it was released in 1975 5 it

operates in 16bit mode and provides only

basic UI navigation using the keyboard

it supports up to 14 partitions and a

maximum partition size of 2 tbytes it

takes a bit longer time to boot the

system it supports only password

protection UAV is a modern way to save

firmware it was released in 2002 it

operates in 32-bit and 64-bit modes it

provides graphical UI navigation it

supports up to 128 partitions and a

maximum partition size of 18x xtes it

takes only a few seconds to boot the

system and supports secure boot

features MBR is a classical way to store

a bootloader program and partition

information it reserves the first 512

bytes of the storage device to save this

information only bios-based systems use

it UAV based systems do not use it they

use GPT to store partition information

and a bootloader program MBR is

non-redundant it does not replicate the

records it contains if if it is corrupt

the system will not boot it supports a

maximum of 14 partitions GPT is a modern

way to store a bootloader program and

partition information to save this

information it uses 4 kilobits dis space

after the first 512 bytes of the hard

disk since it does not modify or use the

reserved dis space for MBR both bios and

UF based systems can use it GPT is

redundant it saves a copy of the

partition information at the end of the

dis it supports a maximum of 28

partitions you can use the entire dis as

a single partition or create multiple

partitions on it usually administrators

create partitions to make Disk

Management easier let us take an example

suppose you have a 2 terabytes hard disk

you want to use it to store text files

media files and script files without any

partition you have to save all three

types of content on the same partition

you can do that but it would make

accessing and managing them difficult

the correct way would be to create and

use three partitions one for each type

you can create a small-sized partition

for text files a meat sized for script

files and a large siiz partition for

media files it makes finding and

managing files much

easier there are two types of partitions

standard and advanced you can use any

type based on disk size and your

requirements standard partitions are

easy all operating systems by default

include tools and utilities to create an

manage them they are mainly used on

personal computers they do not need any

additional discs you can create and use

them on a single dis GPT and MBR are

used to store standard partitions

information GPT supports a maximum of

128 partitions it uses a flat

partitioning scheme all partitions are

equal you can create them in a sequence

starting from one MBR supports a maximum

of 14 partitions it uses a bit complex

partitioning scheme it divides partition

into three types primary extended and

logical you can create a maximum of four

primary partitions if you need more

partitions you need to convert the last

primary partition into an extended

partition an extended partition works

like a container for logical partitions

you can create a maximum of 11 logical

partitions inside the extended partition

an extended partition is not used to

store data it is used to store only

logical partitions Advanced partitions

are complex they are mainly used used on

server systems and usually need more

than one dis by default operating

systems may or may not include tools and

utilities to create and manage them if

tools and utilities are not installed by

default you need to install them before

you can create and use Advanced

partitions lvm and ridar advanced

partitions lvm creates a logical pool

from standard partitions and uses it to

create logical partitions the main

difference between standard partitions

and lvm logical partitions is that

standard partitions are fixed while LV

VM logical partitions are flexible you

cannot extend or shrink the size of a

standard partition however you can

increase or decrease the size of a lvm

logical partition raid creates an array

of diss it can store the same data on

multiple diss it is mainly used to

create the real-time backup of

data a hard disk contains tracks and

sectors it uses tracks to organize

sectors and sectors to save data when we

save a file on it the operating system

saves the file on any of these sectors

it uses an index known as a file system

to know which file is stored in which

sector a file system is a database of

all files and directories stored on the

hard disk it also specifies conventions

for file names such as the maximum

number and types of characters we can

use in a file name along with the names

and locations of the files it also

stores information about their sizes

attributes and metadata different

operating systems use different file

systems ntf s ext4 and xfs are widely

used file

systems that's all for this video if you

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