1. Essential Computing Concepts
© Math & Computer Department
Foundation Program
Fall 2006

2. Information System An Information System has the following parts:
People: the most important part
Hardware: consists of the equipment: keyboard, monitor, etc…
Software: refers to the programs and its purpose is to convert data into information
Data: unprocessed facts, and once processed, it becomes information
Procedures: guidelines for people to follow when using software, hardware, and data

3. What is a Computer System?
Hardware
Software
Equipment
Programs

4. Central processing unit
Computer System
Central processing unit
(CPU)
Input
Memory
Output
Hard Disk

5. Main Parts of a PC include:
The System Unit
CPU
Memory or RAM (Temporary or Primary Storage)
Input / Output Devices
Secondary storage Devices
Communication Devices
( Sends and receives data and
programs from one computer or
secondary storage device to
another )

6. The System Unit
The Motherboard, RAM, ROM, Hard Drive, Video Card and Power Supply are all inside the System Unit
Ports are used to connect Input, Output, Secondary Storage and Communication devices to the System Unit

7. Picture of a Motherboard

8. The Motherboard
Everything inside the system unit is connected to the motherboard
Cards are plugged into slots on the Motherboard
Example: Graphics Card, Sound Card, Network Card
Hard drive is connected by cables
CPU is a silicon chip on the motherboard

9. The CPU Central Processing Unit (or Processor)
The brain of the computer
Does all the Calculation and Processing
Contains:
Control Unit: interprets instructions
Arithmetic Logic Unit (ALU): performs logical & arithmetic operations
Cache memory: where the computer gets programs and data to execute

10. The speed of the CPU Measured in Hertz 1 Hertz = 1 cycle per second
1 cycle = 1 addition
Megahertz = 1,000,000 cycles/second
Gigahertz = 1,000,000,000 cycles/second
Typical speed of modern CPU is 3 GHz

11. Random Access Memory (RAM)
Electronic Components that temporarily store data (numbers, text, graphics, etc) being processed
All programs and data are loaded into RAM
Volatile – is deleted when the computer is switched off

12. Read Only Memory (ROM)
A set of chips containing permanent (non-changeable) instructions to make the computer start working
Can be read but cannot be written to
ROM-BIOS – When the computer is switched on, these instructions check the computer and load the operating system into RAM
Test is called POST
Power On System Test

13. Input Devices Mouse Keyboard
Scanner, video camera, light pen, joystick etc.

14. Output Devices Monitor/Screen (VDU – Visual Display Unit) Printers
Laser printers
Inkjet printers
Plotters, speakers etc.

15. Secondary Storage Devices
Provide Permanent Storage
Common Storage Devices:
Hard (Fixed) Disk : Consists of 1 or more rigid metal platters coated with a metal oxide material for recording.
Floppy disk : Consists of thin, circular, flexible plastic disk with magnetic coating.
CD (Compact Disk) : Flat, round, portable, metal storage. Uses laser technology.
DVD (Digital Versatile Disk)

16. RAM
CPU CD
HARD DISK

17. Monitor Size and Resolution
Different sizes: 17”, 19”, 21”
Resolution is expressed in pixels (such as 800 x 600 or 1024 x 768)
The higher the resolution, the more you can see. Larger monitors let you run at higher resolutions: e.g., 19” can run 1024 x 768 comfortably
A graphics card (video display adapter) speeds processing

18. Ports and Buses Located on the system unit
Used to connect peripherals (any outside device you can attach to your computer)
Types:
Serial Port
Parallel Port
Universal Serial Bus (USB)

19. Serial Ports Serial – data transferred bit by bit
Normally two: COM1 and COM2
Used to connect devices such as modems

20. Parallel Ports Transfer more than one bit in one read/write
Usually two: LPT1 and LPT2
Used to connect devices such as printers

21. Universal Serial Bus (USB)
Serial – one bit in one read/write
Used for devices like scanners, digital cameras and flash drives

22. Types of Computers
Supercomputer: The fastest and most expensive high-capacity computers used by very large organizations
Mainframe: Large computers, capable of great processing speeds and data storage
Minicomputer: midrange computers used by medium-sized companies
Microcomputer: Least powerful, small computers, but most widely used (desktop, Notebook or laptop, and Personal Digital Assistants)

23. Computer = Hardware + Software
Hardware : refers to the Equipment
Software : refers to the Programs
A program is a set of instructions which tells the computer how to do its work

24. Types of Software
System Software : Programs to control the operation of the computer
E.g. Operating System (Windows, Unix, Linux etc),
Utility Programs, Device Drivers
Application Software : Programs for various applications
E.g. Programs for word processing, business, scientific and other applications such as Microsoft Office which consists of MS Word, MS Excel etc.

25. Types of Software Hardware System Application
E.g. Operating system such as Windows XP
Hardware
System
S / W
Back-end
Application
Front-end
E.g. End-user programs such as MS Word

26. Connectivity
Connectivity is the capability of your microcomputer to share information with other computers
Central to the concept of connectivity: Network
Network
A communications system connecting two or more computers
The largest network in the world is Internet

27. Data in files Is used to describe facts about something
Common types of files:
Document
Worksheet
Database
Presentation

28. Data Storage
A Bit (short for Binary digit) is the smallest unit of storage in the computer. It represents a pulse of electricity: Off = 0, On = 1
All numbers in the computer must be represented by Bits (0 or 1). We cannot do this with decimal numbers, so instead we use binary numbers
Storage capacity: The amount of information that can be stored in a secondary storage device or in memory

29. Storage Capacity Temporary Storage Permanent Storage
Random Access Memory (RAM) 256MB – 1GB
Permanent Storage
Floppy Disk MB
Hard Disk – 120 GB
CD (Compact Disk) about 700 MB
DVD (Digital Versatile Disk) GB
DAT tapes GB

30. Binary Numbering System
Base 2
Consists of only two digits: 0 and 1
Converting a binary number to decimal (Example):
1101 (binary) = 1*23 + 1*22 + 0*21 + 1*20
= 1*8 + 1*4 + 0*2 + 1*1 =
= 13 (decimal)

31. Bits & Bytes
Bit:
All computers work on a binary numbering system, i.e. they process data in one's or zero's. This 1 or 0 level of storage is called a bit.
Byte:
A byte consists of eight bits.
Kilobyte:
A kilobyte (KB) consists of 1024 bytes, approx 1,000 bytes.
Megabyte:
A megabyte (MB) consists of 1024 kilobytes approx 1,000,000 bytes.
Gigabyte:
A gigabyte (GB) consists of 1024 megabytes approx 1,000,000,000 bytes.

32. Representing Data
The ASCII code (American Standard Code for Information Interchange) is used
“A”  65 ( )
“9”  57 ( )
“?”  63 ( )
“£”  163 ( )
1 Byte = 8 Bits. Data is represented in Bytes One character requires 1 byte of storage.
Storage Capacity is measured in Bytes (B, KB, MB, GB)

33. Occupational Health & Safety
Using the computer for long periods of time, may pose risk to health.
Ergonomics:
Position of the monitor – Frame above screen should be level with eyes, so
that you look slightly down. Distance should be less than an arm’s length.
Avoid screen reflection and flickering.
Posture of the user – Chair back upright, lower back supported, feet flat on
floor, Forearms should be horizontal, wrists straight and task materials
within comfortable reach of both hands.
Preventive exercises should be done before commencing work, during work and after lunch breaks.
Eye exercises: Take frequent short rests: Look away from screen towards
objects ft away, or look outside the window far out, or close your eyes.
Muscle exercises: Do neck exercises. After every hour walk around, stretch
all muscles and perform whatever relieves the feeling of muscle fatigue/strain
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