Topic1:

Overview of a computer

system

CSC118 Fundamental of Algorithm

Development

What is computer?

Is an electronic device, operating under the

control of instructions stored in its own

memory, that can accept data, process the

data according to specified rules, produce

results, and store the results for the future

use.

Data vs Information??

Advantages & Disadvantages of using

computers:-??

Advantages & Disadvantages

Advantages Disadvantages

Speed Violation of privacy

Reliability Impact on labor force

Consistency Public safety

Storage Health Risks

Communications Impact on Environment

The components of a computer

Known as hardware.

These component include:

1. Input Devices

2. Output Devices

3. System Unit

4. Storage Devices

5. Communications Devices

Basic Concepts of Computer

Hardware

CPU

(Central Processing Unit)Input

Device

Output

Device

Secondary memory

Primary Memory

Input device – allows to enter data and

instructions into a computer.

Output devices – conveys information to one or

more people

System unit – contains electronics components

of the computer that are used to process data.

Motherboard is a circuit board that contains

circuitry of a system unit

2 main component on the motherboard –

processor and memory

Storage devices – records (writes) and/or

retrieves (reads) items to and from storage

media. Often function as a source of input

because transfer items from storage to

memory.

Communication devices – enables

computer to send (transmit) and retrieve data,

instructions and information to and from one

or more computers.

System unit

All computer system have a system unit. System unit contains

most of the computer’s electronic components.

The basic components in the system unit, including the system

board, microprocessor, memory, system clock, expansion

slots and cards, bus lines, ports, cables and power supply

units.

System board – connects all system components to one

another.

Microprocessor – controls operations and performs arithmetic

and logical operations.

Memory – holds data, instructions, and information.

System clock – emits a beats or pulse that sets the operating

pace for all of the components in the system unit.

Expansion slots – provide connections for expansion cards to

the system board.

… System unit

Expansion card – allow external devices to connect to and

expand a computer’s capability.

Bus lines – provide data pathways that connect various

system components.

Ports – socket for external devices to connect to the system

unit.

Cables – connect exterior devices to the system unit via the

ports.

Power supply unit – converts AC (alternating current) to DC

(direct current), providing power to the system unit.

System board

The system board is also known as the main board or

motherboard.

It is the communications medium for the entire computer system.

Every components of the system unit connects to the system

board.

It acts as a data path allowing the various components to

communicate with one another.

For example, external devices such as the keyboard, mouse and

monitor could not communicate with the system unit without the

system board.

It is a large flat circuit board covered with a variety of different

electronic components including sockets, slots and bus lines.

Microprocessor

In a microcomputer system, the central processing unit (CPU) or processor is contained on a single chip called microprocessor.

The microprocessor is “brains” of the computer system.

It has two basic components:

1. Control unit :

Tells the rest of computer system how to carry out a program’s instructions.

It directs the movement of electronic signals between memory, which temporarily holds data, instructions, and processed information, and the arithmetic logic unit.

It also directs these control signals between the CPU and input/output devices.

2. Arithmetic logic unit :

Usually called ALU, performs two types of operations: arithmetic and logical.

Arithmetic operations as you might expect, are the fundamental math operation (addition, subtraction, multiplication and division).

Logical operations consist of comparison of two pieces of data (=, <, >)

Microprocessor chip

Chip capacities are often expressed in word sizes. A word is the number of bits (such as 16, 32, or 64) that can be accessed at one time by the CPU.

The more bits in a word, the more powerful and faster the computer is.

Eight bits group together to form a byte. So, a 32-bit-word computer can access 4 bytes at a time. Then, a 64-bit-word computer can access 8 bytes at a time. (Therefore, the computer designed to process 64-bit-word is faster).

The two most significant recent developments in microprocessors are:

1. 64-bit processor

powerful and faster microcomputer.

2. Dual-core chip

provides two separate and independent CPUs

allows a single computer to run two programs at the same time –parallel processing

Memory

Memory is a holding area for data, instructions, and information.

Like microprocessors, memory is contained on chips connected to

the system board.

There are three well-known types of memory chips:

1. Random-access memory (RAM)

Hold the program (sequence of instructions) and data that the CPU

is presently processing.

Called as temporary or volatile storage – everything in most types

of RAM is lost as soon as the microcomputer is turned off (also lost

if there is a power failure or other disruption of the electric).

Cache memory or RAM cache improves processing by acting as a

temporary high-speed holding area between the memory and the

CPU computer detects which information in RAM is most

frequently used. It copies that information into the cache. When

needed, the CPU can quickly access the information from the

cache.

… Memory2. Read-only memory (ROM)

ROM chips have programs built into them at the factory.

Unlike RAM chip, ROM chips are not volatile and cannot be changed

by the user.

“Read only” means that the CPU can read, or retrieve data and

programs written on the ROM chip. However, the computer cannot

write (encode or change) the information or instructions.

Typically contain special instructions for detailed computer operations.

For example: instructions to start a computer.

3. Complementary metal-oxide semiconductor (CMOS)

CMOS chip provides flexibility and expandability for a computer

system.

It contains essential information that is required every time the

computer system is turned on - current date and time, amount of RAM,

type of keyboard, mouse, monitor and disk drive.

Unlike RAM, it is powered by a battery and does not lose its contents

when the power is turned off. Unlike ROM, its contents can be

changed to reflect changes in the computer system – such as

increased RAM and new hardware devices.

Expansion slots and cards

Most microcomputers have open architecture – allow users to expand their systems by providing expansion slots on the system board.

Users can insert optional devices known as expansion cardsinto these slots.

There are a wide range of different types of expansion cards. Some of the most commonly used expansion cards are:

1. Video cards: also known as graphics cards. These cards connect the system board to the computer’s monitor. The cards convert the internal electronic signals to video signals so they can be displayed on the monitor.

2. Sound cards: accept audio input from a microphone and convert it into a form that can be processed by the computer. These cards convert internal electronic signals to audio signals so they can be heard from external speakers.

3. Modem cards: also known as internal modem. These cards allow distant computer to communicate with one another by converting electronic signals from within the system unit into electronic signals that can travel over telephone lines and other types of connection.

… Expansion slots and cards

3. Network interface cards (NIC): also known as network adapter

cards, are used to connect a computer to one or more other

computers – users can share data, programs and hardware. NIC

typically connects the system unit to a cable that connects to the

network.

4. TV tuner cards: can watch television, capture video, and surf the

internet at the same time.

Expansion cards fit into slots on the system board

Bus lines

A bus line also known simply as a bus – connects the parts of the CPU to each other.

Buses also link the CPU to various other components on the system board.

A bus is a pathway for bits representing data and instructions. The number of bits that can be travel simultaneously down a bus is known as the bus width.

A bus is similar to a multilane highway that moves bit rather than cars from one location to another. The number of traffic lanes determines the bus width.

A highway (bus line) with more traffic lanes (bus width) can move traffic (data and instructions) faster – is an important factor relating to the speed and power for a particular computer. For example, a 64-bit bus is twice as fast as a 32-bit bus.

Every computer system has two basic categories of buses:

1. System buses: connect the CPU to the memory on the system board.

2. Expansion buses: connect the CPU to other components on the system board.

Figure 8: Bus

Ports

A port is socket for external devices to connect to the system unit.

Some ports connect directly to the system board while other connect to cards that are inserted into slots on the system board.

Many ports, like the mouse, keyboard, and video ports, are for specific devices. Others, like those listed below, can be used for a variety of different devices.

1. Serial ports:

are used for a wide of purposes. They are often used to connect a mouse, keyboard, modem, and many other devices to the system unit.

Send data one bit at a time and very good for sending information over a long distance.

2. Parallel ports:

are used to connect external devices that need to send or receive a lot of data over a short distance.

Typically send eight bits of data simultaneously across eight parallel wires.

Mostly used to connect printers to the system unit.

… Ports

3. Universal serial bus (USB) ports:

gradually replacing serial and parallel ports.

Faster, and one USB port can be used to connect several

devices to the system unit.

4. FireWire ports:

also known as high-performance serial bus (HPSB) ports.

As fast as USB 2.0 ports and provide connections to

specialized FireWire devices such as camcorders.

Ports

printer

Portable

media player

CD/DVD

drive

Web cam

monitor

speakers

mouse

keyboard

microphone

Digital

camera

Hard disk

drive

scanner

External

Hard disk

Memory card

modemUSB flash

drive Card reader/

writer

Excercise 1: Match with correct device

… Computer hardware

Input devices – for capturing information

Output devices – for presenting information

System unit – for creating new information and data processing

Storage – for storing information

Communication devices – for communicating information

Connecting devices – for moving information to and from various hardware

HARDWARE

Keyboard, Mouse, Microphone, Scanner, Digital Camera and Web

Cam

Monitor, Speaker and Portable Media Player

Memory ,Central Processing Unit (CPU), Motherboard, Power Supply

Hard Disk, Compact Disc, USB Flash Drive, Memory Card

Modem and Network Card

Cables, Telephone Lines, Satellite

Computer Software

Also called a program, is a series of

instructions that tells the computer what to

do and how to do.

With a graphical user interface (GUI), we

can interact with the software using text,

graphics and visual images such as icons.

2 categories of software:-

1. System Software

2. Application Software

1. System Software

consists of programs that control or maintain

the operations of the computer and its

devices.

Serves as the interface between the user,

the application software and the computer’s

hardware.

2 types:

1. Operating system.

2. Utility program

Operating system – set of a programs that

coordinates all the activities among computer

hardware devices. Example Windows Vista,

Windows XP and Mac OS X.

Utility program – allows a user to perform

maintenance-type tasks usually related to

managing a computer, its devices, or its

programs. For example utility programs to

transfer digital photos to a CD or DVD.

2. Application Software

Consists of programs designed to make

users more productive and/or assist them

with personal tasks.

A widely used is a Web browser. Other

popular includes word processing software,

spreadsheet software, database software and

presentation graphics software.

Windows NT

Microsoft

PowerPoint

Anti virus

software Paint

program

Printers

installer

Windows

2000

Windows

Media

Player

Ms Excel

Exercise 2:

Find the category of software

Computer Software

SOFTWARE

System Software

Application Software

1. Uses to run computer.2. To control and maintain the operation of

computer and its devices.3. Serve as the interface between computer

hardware, user and application software.4. Example: Operating System (Windows,

Linux,Unix) and Utility Program (Antivirus).

1. Program designed to make user more productive.

2. Assist user to with personal task and perform specific information processing task such as writing term paper, and creating presentation slide, and writing and program.

3. Example: Microsoft Office 2007, Microsoft PowerPoint 2007,spreadsheets,games, inventory program.

Categories of Computers

1. Personal Computers (PC)

2. Mobile Computers and Mobile Devices

3. Game Consoles

4. Servers

5. Mainframes

6. Supercomputers

7. Embedded Computers

Desktop

Notebook Tablet

PC

Smart

Phone

laptop

Sony’s

PS 3

Handheld

computer

PDA

Exercise 3: Name the correct categories of computers

UiTM

network

Online

banking

Nuclear

Energy

research