1

Topic 22.0 COMPUTER HARDWARE

2

Outcome

At the end of this class, you will be able to :

a) Understand the basic components of computer system.

b) Identify the power supply for a system.

3

Outline 2.1 Basic components of computer system

Basic diagram of computer system   Input, output, processing and storage devices    Functions of primary and secondary storage devices.   Characteristics of primary and secondary storage devices   Appropriate input devices for a particular purpose

2.2 Power supply for a system

Basic function of power supply unit Suitable power supply unit for a particular computer system

Advantages of using uninterruptible power supply (UPS)

4

2.1 Basic components of computer system

5

Diagram Of Computer System

6

central processing unit (CPU)• It carries out the instructions of a

computer program by performing the basic arithmetical, logical, and input/output operations of the system

• Two components of CPU:• arithmetic logic unit (ALU)

• It performs arithmetic and logical operations• control unit (CU)

• It extracts instructions from memory and decodes and executes them

Computer hardware

7

What is computer hardware?

• Hardware is parts in computer that can be seen and touched.

• 4 basic categories of hardware :i. Input devicesii. Output devicesiii. Processing devicesiv. Storage devices

8

i. Input devices

Input device is an intermediary device that allows user to enter data and instruction to computer’s memory.

• Example: mouse, microphone, keyboard & scanner

9

ii. Output Device

• It is used to generate information that has been executed by the computer for the user.

• Example: printer, monitor and speaker.

10

iii. Processing Device• Processing devices in a computer are responsible for controlling the storage and retrieval of information.

• It considered the 'brain' of your computer, it is identified by manufacturer, model, and processing speed in hertz (Hz)

• CPU (Center Processing Unit), sometimes named as processor, is an electronic device that executes instruction in computer.

• The information is processed by the computer processor (CPU), which performs data calculations, data comparisons, and data copying with the information from the processing devices.

• The CPU then saves that information to the computer memory (RAM).

11

12

iv. Storage Device

It is used to store and access data, instructions and information from memory.

There are two storage devices :i. Primary storage (e.g RAM)

ii. Secondary storage (e.g hard drive)

13

Secondary Storage

14

Functions Of Primary & Secondary Storage Devices

i. Primary Storage• Primary storage is closely connected to the CPU and is

used for temporary storage of data and instructions during processing.

• Primary storage is fast; secondary storage is slow (relatively).

• Primary storage is volatile (i.e. contents are lost when power is removed); secondary storage is non-volatile.

• Primary storage is based on electronic technology; secondary storage is usually based on magnetic (or optical) and mechanical technologies.

 

15

i. Primary Storage

• Types of Primary Storageo RAM (``Random Access Memory''). o Called ``RAM'' because any location in the memory can be directly

accessed in the same amount of time as any other location. o ROM (``Read Only Memory'').o Is what it says: contains programs and/or data ``burned in'' at the

time of manufacture. o Commonly used to contain programs to ``boot up'' the computer

when it is switched on. o PROM (``Programmable Read Only Memory''). o ROM which is ``blank'' and into which programs and/or data can be

written, but only once.o EPROM (``Erasable Programmable Read Only Memory''). o PROM which can be erased, usually by exposure to UV light through

a transparent window above the chip.

16

ii. Secondary Storage

• The function of secondary storage is the long-term retention of data in a computer system.

• It is non-volatile and not cleared when the computer is powered off and back on.

• Unlike primary storage, secondary storage also doesn't directly access the computer's CPU.

17

ii. Storage Device

• Types of secondary storage :o Floppy disketteo CD-ROM disco CD-R and CD-RW disco Cloud storageo DVD-R, DVD+R, DVD-RW, and DVD+RW disco Jump drive and USB flash driveo Hard driveo Memory cardo Memory sticko Tape cassetteo Zip diskette

18

Primary Storage vs Secondary Storage

Primary Secondary• known as main memory, is used to hold pieces of program instructions and data, intermediate result

• known as auxiliary storage, is used to take care of the limitations of the primary storage

• expensive than secondary • cheaper than primary

• volatile and cleared when the computer is powered off and back on

• non-volatile and not cleared when the computer is powered off and back on.

• faster but doesn't store data persistently

• slower in both read and write access

• directly access the computer's CPU

• doesn't directly access the computer's CPU

19

Appropriate Input Devices For A Particular Purpose

• Purpose• entering data into a computer system• issuing instructions (commands) to a computer

• Input device• transforms data from the user into a form that a computer system can process

• together with appropriate software (device drivers)

• Need to specify the objects and actions of interaction• what should be done• how can it be done

• Logical equivalence of input devices • different devices can be used for the same input tasks• examples

• mouse, trackpad, pen• mouse, cursor keys• keyboard, pen

20© Franz J. Kurfess

Categories of Input Devices• Keys and Buttons

• keyboards • most common (QWERTY, Dvorak, chord, alphabetic)

• keypads• alphabetic, numeric, telephone, calculator, special purpose (remote

controls)

• buttons• discrete entry device• initiates the transfer of a signal when pressed

• function keys• invoke specific actions

• cursor keys• navigation on the screen

[Mustillo]

23

Particular Purpose of Input DeviceDevices Image Purpose

Bar Code Reader Used where the amount of data is limited and is not subject to rapid change. Example : supermarket

Optical Character Reader (OCR)

Can handle a variety of data.

Scanner Used for inputting large amounts of text, diagrams and pictures.

24

Particular Purpose of Input DeviceDevices Image Purpose

Magnetic Ink Character Recognition (MICR)

Similar to OCR, but more reliable.

Used mostly in banks.

Footmouse A type of computer mouse that gives the users the ability to move the cursor and click the mouse buttons with their feet.

It is primarily used by users with disabilities or with high-back or neck problems.

Graphic Tablet Movement of a stylus across a surface causes a cursor to move across the screen or a line to be drawn. Very good for graphical input.

25

Particular Purpose of Input Device

Devices Image Purpose

Joystick Often used for cursor-positioning tasks where precision is required.

Requires a high level of concentration to use.

Fine control is limited.

Trackball A computer cursor control device used in many notebook and laptop computers.

The trackball is usually located in front of the keyboard toward the user. 

26

2.2 Power supply for a system

27

Basic function of power supply unit

The power supply for your personal computer gives your machine all the

different voltages it needs to operate properly.

It is able to take the AC (alternating current) voltage from your home electrical outlet and convert it to the lower DC (direct current) voltage that your computer needs.

You can identify the power supply as the metal box that is usually located in a corner of the PC case.

Sometimes you can see the power supply at the back of your PC because it holds the power cord receptacle and the computer's cooling fan.

28

What Is Uninterruptible Power Supply (Ups)?

• An uninterruptible power supply (UPS) is a device that has an alternate source of energy that can provide power when the primary power source is temporarily disabled

• The switchover time must be small enough to not cause a disruption in the operation of the loads.

29

Advantages of using Uninterruptible Power Supply (UPS)

• Protects against multiple types of power disturbances• Only device that protects against an outage• Offers protection against

Equipment not operating properlyComputer and equipment damageData lossTime and expense to recover back to where you were, if

even possible

30

Causes Of Power Disturbances• Storm activity – lightning, wind, ice• Objects coming in contact with power line and

tripping breaker – tree branches, animals, other• Utility fault clearing• Construction activity• Equipment failure• Overloading• Load switching• Non-linear loads• Poor grounding

31

THE END

Any Question?