This document provides an overview of the key components of a computer system. It discusses that a computer is an electronic device that can accept data as input, process it, produce output, and store results. The main components are the hardware (physical parts like the system unit, storage and input/output devices), and software programs. The system unit contains the central components like the motherboard, CPU, memory and power supply. Expansion slots allow adding capabilities. Buses connect the components and ports provide connections for external devices. The document also distinguishes system software from application software.

1. Topic1:
Overview of a computer
system
CSC118 Fundamental of Algorithm
Development

2. 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:-??

3. Advantages & Disadvantages
Advantages Disadvantages
Speed Violation of privacy
Reliability Impact on labor force
Consistency Public safety
Storage Health Risks
Communications Impact on Environment

4. 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

5. Basic Concepts of Computer
Hardware
CPU
(Central Processing Unit)
Input
Device
Output
Device
Secondary memory
Primary Memory

6.  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

7.  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.

8. 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.

9. … 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.

10. 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.

11. 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 (=, <, >)

12. 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

13. 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.

14. … Memory
2. 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.

15. 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 cards
into 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.

16. … 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

17. 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

18. 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.

19. … 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

20. Excercise 1: Match with correct device
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
USB flash modem
drive Card reader/
writer

21. … 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
H
A
R
D
W
A
R
E
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

22. 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

23. 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

24.  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.

25. 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.

26. Windows NT
Microsoft
PowerPoint
Anti virus
software Paint
program
Windows
Printers
installer
2000
Windows
Media
Player
Ms Excel
Exercise 2:
Find the category of software

27. Computer Software
S
O
F
T
W
A
R
E
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.

28. 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

29. Desktop
Notebook Tablet
PC
Smart
Phone
laptop
Sony’s
PS 3
PDA
Handheld
computer
UiTM
network
Online
banking
Nuclear
Energy
research
Exercise 3: Name the correct categories of computers