Hubert Kairuki Memorial University Kaizilege Karoma

2 Introduction to Computers

3 Contents: The term, computer Categories of computers Basic concepts The components of a computer Advantages & Disadvantages of using computers

4 What Is A Computer? A computer is an electronic device, that can accept data (input), manipulate data (process), produce information (output) from the processing and store information (storage). Generally, the term is used to describe a collection of devices that function together as a system.

5 What Does A Computer Do? Computers can perform four general operations, which comprise the information processing cycle. Input Process Output Storage

6 Categories of Computers Personal Computers (desktop) Mobile Computers (PDA, Laptop) Mini Computers Mainframe computers Super computers Embedded Computers

7 Two main parts of a computer Hardware: The physical equipment that used in a computer system “Touchable part of a computer”

8 … Two main parts of a computer Software: The program that can be used with a computer system. “Untouchable part of a computer”

9 Computer Software Computer software is the key to productive use of computers. Software can be categorized into two types: Operating system software Application software.

10 Operating System Software Operating system software tells the computer how to perform the functions of loading, storing and executing an application and how to transfer data. Today, many computers use an operating system that has a graphical user interface (GUI) that provides visual clues such as icons to help the user.

11 Example of Operating System Software DOS Windows ( ‘ 95, ‘ 98, Me, 2000, XP, Windows Vista, Windows 7) Linux (Ubuntu, Fedora, RedHat, Suse, Debian) Unix OS/2

12 Application Software Application Software consists of programs that tell a computer how to produce information. Some of the more commonly used packages are: Word processing spreadsheet Database Presentation Software

13 What Are The Primary Components Of A Computer ? Input devices. Central Processing Unit (containing the control unit and the arithmetic/logic unit). Memory. Output devices. Storage devices.

14 Devices that comprise a computer system Monitor Keyboard System Unit Speaker Mouse Scanner Storage Devices

15 Input Devices Keyboard. Mouse. Scanner Barcode reader CD-ROM

16 Output Devices A monitor (Computer screen) Printer Speakers CD-ROM

17 The Central processing Unit The central processing unit (CPU) contains electronic circuits that cause processing to occur. The CPU interprets instructions to the computer, performs the logical and arithmetic processing operations, and causes the input and output operations to occur. It is considered the “ brain ” of the computer.

18 Networks Computer can communicate to each other, this is possible by implementing the network.

19 Networks LAN LAN A network that connects computers in a limited geographical area A network that connects computers in a limited geographical area School / University School / University Laboratory / Hospital Laboratory / Hospital Local business Local business

20 … Networks WAN A network that covers a large geographical area A network that covers a large geographical area District offices District offices International offices International offices

21 Internet The Internet World ’ s largest Network World ’ s largest Network Millions of computers Millions of computers World wide World wide Reasons for using Reasons for using Sending messages ( ) Sending messages ( ) Accessing information Accessing information Shopping Shopping Meeting or conversing Meeting or conversing Entertainment Entertainment Games Games Magazines Magazines

22 Advantages of using Computers Speed Reliability Consistency Storage Communication

23 Disadvantages of using computers Violation of privacy Public safety Impact on labor force Health risks

24 Safe Computing

25 Unplug before cleaning. Place on a stable surface. Do not use near water or spill liquid on or into any part of the computer. Use grounded power outlet. Do not walk on power cord or allow anything to rest on it. Never insert objects into ventilation slots. Unplug system and have serviced if: Power cord or plug is damaged. Liquid has been spilled into the system. System is dropped or cabinet is damaged. Computer Safety

26  Keep virus protection up to date.  Run ScanDisk periodically.  Don’t use floppy disks with loose shutters.  Dust system frequently.  Keep system away from chalk dust.  Unplug the computer before cleaning.  Do not spray cleaning liquids onto any part of the computer.  Do not block or cover any openings on the monitor or System Unit. Keep Your Computer Healthy

27 Malicious Computer Programs

28 Computer Virus Is a piece of code that is secretly introduced into a system in order to corrupt it or destroy data.

29 Computer Worm Is a self-replicating computer program. It uses a network to send copies of itself to other computers.

30 Trojan Horse Computer program hidden in another good computer program with the purpose of destroying software or collecting information about the use of the computer.

31 Spyware Software that sends information about web surfing habits to its website. Spyware is often installed without the user ’ s knowledge or explicit permission.

32 Adware Software installed on users computer along with other free software. It is used to track your internet habits.

33 Thank you