All language subtitles for 9_The Boot Process

In this lesson,
we're going to learn

how our operating
system starts up.

As an IT support specialist,

you'll probably work on lots

of computers that won't start.

It's important to know the steps

and operating system takes,

so you can help
diagnose the issue.

Booting a computer or starting
a computer comes from

the phrase to pull oneself
up by one's bootstraps.

Basically, it means to start
from nothing and follow

a series of steps to

arrive at a fully
operational system.

When we start up with computer,

will use the term boot.

For most operating systems,

the boot process follows
a general pattern,

much like how we
have different cars

startup in the same way.

Put in the key, turn
on the ignition, etc.

Here's a rundown of
the boot process.

First, the computer
is powered on.

The BIOS/UEFI is a
low-level software that

initializes our
computer's hardware

to make sure everything
is good to go.

Next, the bios UEFI runs
a process called the

power-on self-test, or post.

The post performs a series
of diagnostic tests to

make sure that the computer
is in proper working order.

Next, depending on the bios or

UEFI configuration of boot
device will be selected.

Devices that are attached to

our system, like hard drives,

USB drives, CD drives,

etc, are configured in
a certain boot order.

The devices will be
checked in this order and

the computer will search for

what's known as a bootloader.

The bootloader is
a small program

that loads the operating system.

Once our computer finds

a bootloader on a device
in the listed order,

it will start to
execute this program.

This will then start to load

a larger and more
complex program

and eventually loads
our operating system.

Once the bootloader loads
up our operating system,

our kernel gets loaded.

The kernel controls access
to our computer's resources.

It also loads up
drivers and more so

that our hardware can
talk to our software.

Next, essential system

processes and user space
items are launched.

These include processes
like user login,

spinning up a
desktop environment,

and more which basically

allows us to interact
with our system.

And that's it. After
these simple steps,

you'll be able to get to work.