1

Chapter Two

BIOS Setup Configuration

 2
Outline

 Overview of BIOS
 Function of BIOS
 The Boot Process
 Entering BIOS setup
 Setting boot priority
 BIOS Beep sounds
 3
BIOS Overview

 Starting a computer or a computer-embedded device is

called booting.

 Booting takes place in two steps

 Switching on power supply

 Loading operating system into computer’s main memory.

 4
BIOS Overview

 A special kind of program is required to enable the CPU to

talk to other devices
• A ROM chip stores these programs
• These programs are collectively known as the Basic
Input/Output System(BIOS).
 5
BIOS Overview

 Programs stored on ROM chips are known as firmware

 Programs stored on erasable media are called software

 BIOS is a group of programs.

 ROM is a hardware chip used to store BIOS.

 6
BIOS Overview

 The first program or set of instructions that run when the

computer is switched on is called BIOS or Basic Input Output
System.
 BIOS is a firmware, i.e. a piece of software permanently
programmed into the hardware.
 If a system is already running but needs to be restarted, it is
called rebooting.
 Rebooting may be required if a software or hardware has
been installed or system is unusually slow.
 7
BIOS Overview

 There are two types of booting −

 Cold Booting − When the system is started by switching on the
power supply it is called cold booting.
 The next step in cold booting is loading of BIOS.
 Warm Booting − When the system is already running and
needs to be restarted or rebooted, it is called warm booting.
 Warm booting is faster than cold booting because BIOS is not
reloaded.
 8
BIOS Overview

 A BIOS (Basic Input/Output System) Short for ROM is boot

firmware program that a computer uses to successfully start
operating.
 The BIOS is located on a chip inside of the computer and is
designed in a way that protects it from disk failure.
 When you turn on a PC, the BIOS first conduct a basic
hardware check, called a Power-On Self Test (POST), to
determine whether all of the attachments are present and
working.
 9
BIOS Overview

 Then it loads the operating system into your computer's

random access memory, or RAM.
– Initiated when the computer is turned on, or is reset
– Checks out the system every time the computer boots
 The BIOS also manages data flow between the computer's
operating system and attached devices.
 The BIOS stores the date, the time, and your system
configuration information in a battery-powered, non-volatile
memory chip.
 10
Function of BIOS (1)

 The main functions

of the BIOS are:
 11
Function of BIOS (2)

(i) BIOS Power on Self Test (POST): It is a built-in diagnostic program.

 This self test ensures that the computer has all of the necessary
parts and functionality needed to successfully start itself, such as
use of memory, a keyboard and other parts.
 Then additional tests are done during booting. If errors are
detected during the test, the BIOS instruct the computer to give
a code that reveals the problem.
 Error codes are typically a series of beeps heard shortly after
startup.
 12
Function of BIOS (3)

(ii) Bootstrap Loader: Responsible to boot the operating system.

 The BIOS contains a program known as bootstrap loader whose
responsibility is to search and start the operating system boot
program.
 Then the boot program of operating system controls the
computer system and boots the operating system.
 13
Function of BIOS (4)

(iii) System Service Routines: The BIOS provides various software

routines (subprograms) that can be called by higher-level
software such, as DOS, Windows, or their applications, to perform
different tasks.
 Virtually every task that involves accessing the system
hardware has traditionally been controlled using one or more
of the BIOS programs
 This includes actions like reading and writing from the hard
disk, processing information received from devices, etc.
 14
The Boot Process (1)

 The CPU is the first component that gets initialized when the
computer is turned on.
 It reads a special wire called power good once the power
supply provides the proper voltage to the CPU.
 Every CPU has a built-in memory address with the first line of
the POST program on the system ROM.
 15
The Boot Process (2)

 The last BIOS function called by POST is the bootstrap loader.

 The bootstrap loader loads the operating system either from

the floppy or the hard drive.

 The bootstrap loader generates an error if it cannot find the

bootable disk.
 16
Entering the BIOS on a Dell (1)

 BIOS controls hardware features on your computer such as

enabling or disabling hardware components, monitoring

system temperatures and speeds, or setting boot sequence

to boot the computer from a CD/Hard Disk/Network/USB.

 17
Entering the BIOS on a Dell (2)

Step 1
 Turn on your Dell computer or reboot it.
Step 2
 Press "F2" when the first screen appears. Timing is difficult, so
you may wish to continually press "F2" until you see the
message "Entering Setup…..”.
Step 3
 Use your arrow keys to navigate BIOS. You mouse will be
inoperative in BIOS.
 18
Entering the BIOS on a Dell (3)
 19
BIOS Boot (1)

 BIOS (Basic Input Output Subsystem) are a programmable

chip that controls how information is passed to various
devices in the computer system.
 A typical method to access the BIOS settings screen is to
press ESC, F2, F8 or F10 during the boot sequence.
 BIOS settings allow you to run a boot sequence from a floppy
drive, a hard drive, a CD-ROM drive or an external device.
 You may configure the order that your computer searches
these physical devices for the boot sequence.
 20
BIOS Boot (2)

 The first device in the order list has the first boot priority.

 For example, to boot from a CD-ROM drive instead of a hard

drive, place the CD-ROM drive ahead of the hard drive in
priority.

 Before you set boot priority for a USB device, plug the device
into a USB port.
 21
BIOS Boot (3)

To specify the boot sequence:

 Start the computer and press ESC, F2, F8 or F10 during the
initial startup screen.
 Depending on the BIOS manufacturer, a menu may appear.
 Choose to enter BIOS setup. The BIOS setup utility page
appears.
 Use the arrow keys to select the BOOT tab.
 System devices appear in order of priority.
 22
BIOS Boot (4)

 To give a CD or DVD drive boot sequence priority over the hard drive,
move it to the first position in the list.
 To give a USB device boot sequence priority over the hard drive, do the
following:
 Move the hard drive device to the top of the boot sequence list.
 Expand the hard drive device to display all hard drives.
 Move the USB device to the top of the list of hard drives.
 Save and exit the BIOS setup utility.
 The computer will restart with the changed settings.
 23
BIOS Boot (5)

 Boot Sequence
 24
BIOS Boot (6)

 To set quick boot priority using a device selection menu:

 When the computer starts to boot up, after the manufacturer's ID

screen, press F12 several times. The device selection menu appears.

 Use the up and down arrows to select CD-ROM or an USB Flash Drive.

 To boot from the selected device, press ENTER.

 25
Computer POST and beep codes (1)

 The computer POST (power-on self-test) checks a computer's internal

hardware for compatibility and connection before starting the
remainder of the boot process.

 If the computer passes the POST, the computer may give a single beep
(some computers may beep twice) as it starts and continue to boot.

 However, if the computer fails the POST, the computer will either not
beep or generate a beep code that tells the user the source of the
problem.
 26
Computer POST and beep codes (2)

 When we switch on the power of a computer it literally rediscover itself.

This is done through POST (Power On Self Test).
 During Post the system BIOS communication with all essential hardware
devices like keyboard, mouse, disk drives, RAM, display adaptor etc.
 If one of the device reports on error condition back to the BIOS, then
the BIOS reports this back to the user by using special POST error code.
 It gives message by 2 ways
 Message Error (Numeric and Text Code)
 Beep error
 27
Computer POST and beep codes (3)
 28
Computer POST and beep codes (4)

Message error code

 29
Computer POST and beep codes (5)

Beep error code

Because of the wide variety of different computer manufacturers with this
BIOS, the beep codes may vary.
Here are some of the more common beep codes:
 Beep Code Descriptions
30
1 short DRAM refresh failure.
2 short Parity circuit failure.
3 short Base 64 K RAM failure.
4 short System timer failure.
5 short Process failure.
6 short Keyboard controller Gate A20 error.
7 short Virtual mode exception error.
8 short Display memory Read/Write test failure.
9 short ROM BIOS checksum failure.
10 short CMOS shutdown Read/Write error.
11 short Cache memory error.
1 long, 8 short Display/Retrace test failed.
two-tone siren Low CPU fan speed, voltage level issue.
 31
Beep Code Description
1 long, 2 short Indicates a video error has occurred and the
BIOS cannot initialize the video screen to display
any additional information.
1 long, 3 short Video card not detected (reseat video card) or
bad video card.
Beeps repeating endlessly RAM problem.
Repeated high frequency Overheating processor (CPU).
beeps while PC is running
Repeated beeps alternating Issue with the processor (CPU), possibly
high & low frequency damaged.
AWARD BIOS Beep Code
 Beep Code Description 32

1 beep BIOS ROM corruption or failure.

2 beeps Memory (RAM) not detected.

3 beeps Motherboard failure.

4 beeps Memory (RAM) failure.

5 beeps CMOS battery failure.

6 beeps Video card failure.

7 beeps Bad processor (CPU).

Dell BIOS Beep Code

 33

End of Chapter