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

2. Comp 1 - Essential Computing Concepts
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. A Computer Information System
Guidelines/
Protocol/
Procedures

4. What is a Computer? Hardware Software Equipment Programs Hardware:
Physical parts of the computer that you can touch or see
Software: A computer software is made
up of instructions to perform one or more
tasks e.g. Microsoft Word, Games, etc

5. Comp 1 - Essential Computing Concepts
Any Computer System
Central processing unit
(CPU)
Input
Memory
Output
Hard Disk

6. Main Parts of a PC include:
The System Unit
Input / Output Devices
Secondary storage Devices
Communication Devices
(Sends and receives data and programs from one computer to another )

7. The System Unit
The Motherboard, CPU, 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

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. Comp 1 - Essential Computing Concepts
Motherboard
Extension slots
CPU
(Central Processing Unit)
RAM
Random Access Memory
(Main Memory)
The CPU chip is packaged inside a ceramic case. The chip itself is as small as 3/4".
SIMM stands for Single Inline Memory Module.
Logically ROM and RAM form contiguous memory space; the CPU can’t just write into ROM (and never needs to try). Physically ROM is on a separate chip.
Extension slots are used for plugging in additional adapter boards: Internet adapter, graphics card, sound card, disk controller, etc. In newer systems many of these functions are built directly into the motherboard.
ROM (Read Only Memory)

10. 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

11. 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

12. 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

13. 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

14. Input Devices Mouse Keyboard Scanner video camera light pen Joystick
etc…

15. Output Devices Monitor/Screen (VDU – Visual Display Unit) Printers
Laser printers
Inkjet printers
Plotters
Speakers
etc…

16. Secondary Storage Devices
Provide Permanent Storage
Common Storage Devices are:
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)
Flash Memory: Uses a USB connector

17. Formatting Floppy Disk Tracks and Sectors

18. RAM
CPU CD
HARD DISK

19. 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)

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

21. Parallel Ports Transfer more than one bit in one read/write
Used to connect devices such as printers

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

23. 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)

24. MINICOMPUTER
Midrange computers
used by medium-sized organist ions
SUPERCOMPUTER
Most Powerful computers
Fastest, can perform more
than one trillion calculations
per second
MICROCOMPUTER
Mostly for personal use
E.g. Desktop PC, Laptop, PDA etc
MAINFRAME
Used in large organization
Not as powerful as the
Supercomputer
Capable of very high processing Speeds and data storage

25. 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

26. 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.

27. 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

28. 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

29. 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

30. Data Storage Example: A group of 8 bits = 1 byte 010100102 = 1 byte
All the information are stored in the computer storage devices (such as hard disk) in Binary format
Binary Number System is made up of only two value or numbers: 0 or 1. Hence it is known as Base 2 number system.
A bit is a binary digit having a value 0 or 1.
Example:
 2 bit
 3 bits
10102 4 bits
A group of 8 bits = 1 byte
= 1 byte

31. How your PC sees data
Data representation is the process of changing the data into a form that computers can understand and process.
Most computers are digital devices, devices that work with separate, discrete data, such as the digits 1 and 0.
Some are analog devices, devices that work with a continuous range of data.
A light switch is digital.
The light is either on, represented by a 1, represented by These 1s and 0s are binary digits. Binary digits are also called bits.

32. Now, if you type letter “A” in your computer, how do we know the
number of bits and the bit order of letter “A”?
ASCII EXTENSION CODE
This is a code that represents the characters and their binary code as shown below:
Binary
Symbol   A B C D E F G H   a b c d e f g h
Using the extended ASCII table if you write the following in your PC: “Baba” What will be the binary format in which this data is going to saved by the computer?

33. Binary Storage Capacity
Unit
Value
KB (Kilobyte)
210 Bytes = 1024 Bytes
(approx 1,000 bytes)
MB (Megabyte)
220 Bytes = 1024 KB
(approx 1,000,000 bytes)
GB (Gigabyte)
230 Bytes = 1024 MB
TB (Terabyte)
240 Bytes = 1024 GB

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

35. 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)

36. Comp 1 - Essential Computing Concepts
Storage Capacity
Temporary 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

37. 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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