Booting

Question 1

Stages of booting:

Answer 1

1. Firmware
2. Boot loader
3. Operating system

Question 2

Firmware

Answer 2

• When we turn on the power of a computer, the CPU will start
  to execute instructions on a well defined address.
  – The motherboard is built in such a way that the CPU will find a
  pre-installed program in a read-only or flash memory (ROM).
  – This program is called the firmware of the system but is often
  referred to as the BIOS (Basic Input/Output System) since this
  was the name used on IBM compatible PCs

Question 3

The role of the firmware

Answer 3

The role of the firmware is to :
- detect memory
modules and external devices,
- set clock speeds
and monitor fans,
- perform a system test to verify
that all hardware is functioning (Power-On Self
Test (POST)) etc.

Question 4

MBR

Answer 4

– When the BIOS has performed the initial testing of the
system it will locate the primary disk and read the first
segment of 512 bytes.
– This segment is called the Master Boot Record (MBR).
– The BIOS does not know anything about file systems so
one can only place the master boot record at a well
defined position on disk.
– The master boot record is a very small program that will
almost immediately start to read a larger program from
disk.

Question 5

Boot loader

Answer 5

– The master boot record is a very small program that will
almost immediately start to read a larger program from
disk.
* This could be an embedded program or an operating system but
in most cases it is something called a boot loader
- The boot loader (also called boot manager) is
generally a small program that places the operating
system of a computer into memory or RAM.

Question 6

Boot loader focuses on

Answer 6

It focuses on loading and starting the boot-time
tasks and processes found within the operating
system.

Question 7

Once the boot loader has determined which
operating system to start, …

Answer 7

• Once the boot loader has determined which
  operating system to start, it will read the kernel
  from disk and jump to its first instruction.
  – Once this is done, the operating system will take
  control.

Question 8

Operating System

Answer 8

– The operating system will start by taking control
over the hardware.
– It will move to 64-bit mode (if that is not already
done), create a stack, set up the interrupt
descriptor table, initialize virtual memory etc.
– It will then organize the task scheduler, the file
system and hundreds of other things before it
launches services for users to access

Question 9

Types of Booting

Answer 9

– Cold Booting
– Warm Booting

Question 10

Cold Booting

Answer 10

– A cold boot is also called a hard boot.
– It is the process when we first start the computer.
– In other words, when the computer is started from
its initial state by pressing the power button it is
called cold boot.
– The instructions are read from the ROM and the
operating system is loaded in the main memory

Question 11

Warm Booting

Answer 11

– Warm Boot is also called soft boot.
– It refers to when we restart the computer.
– Here, the computer does not start from the initial
state.
– When the system gets stuck sometimes it is
required to restart it while it is ON.
– Therefore, in this condition, the warm boot takes
place.
– Restart button or CTRL+ALT+DELETE keys are used
for warm boot