Introduction to ComputersLecture By K. Ezirim

What is a Computer?• An electronic device

– Desktops, Notebooks, Mobile Devices, Calculators etc.

• Require instructions to operate• Comprises of

– Hardware– Software

Basic operations of Computers• Input – accept data for processing• Process – process data according to

specified instructions/rules• Output – produce results• Storage – store results for future use

Computers are powerful?• Performs information processing with

– High speed– Reliability– Accuracy

• Store huge amount of data and information• Communicates with other computers

Computer Data and Information • Data

– Collection of unprocessed information– Examples: text, numbers, images, audio,

video• Information

– Outcome of processed data– Conveys meaning and is useful– Can be stored in memory

Computer Users• People that use computers

– Computer users, end users, or simply users• Green computing

– Users and manufacture contributing to reduce environmental impact of computing

– Reduced electricity and waste generated

Hardware Components

• Input devices• Processor• Memory• Output devices• Storage devices• Communication devices

System Unit and Peripherals• System Unit

– Processor, Memory and Storage devices• Peripherals

– Input and output devices – Also storage and communication devices

Input Devices• Keyboards• Mouse• Touchpads• Stylus • Touchscreen• Microphone• Camera

System Unit• Motherboard

– main circuit board of the system unit. – Other electronic components are attached to it– Such as sound card, video card

• Processor, also called the Central Processing Unit

• Memory – RAM, measured in bytes

Storage Devices• Hard disks• Portable Hard disks• Flash memory storage

– Memory cards

• Optical disks – CDs, DVDs, Blu-ray disks• Cloud storage – internet service that provide

storage (free/paid)

Output Devices• Printers• Headphones• Speakers• Data Projectors• Monitors etc.

Communication Devices• Enables computers to exchange

information (send and receive)• Transmission media

– Cables, telephone lines, cellular radio networks, and satellites

– Wireless - no physical lines or wires eg. Satellites, cellular radio networks.

Computer Software• Also called program• Usually comes with a user interface

Graphic User Interface (GUI)• Installing and Uninstalling• Divided into System and Application

Software

System Software• Programs that control the operations of a

computer• Operating Systems – coordinates all the

activities among computer hardware devices– Microsoft Windows (Microsoft)– Mac OS (Apple)

• Utility Program – allows users to perform maintenance

Application Software• Includes all applications designed to

– make users more productive– Assist with personal task

• Examples– Word Processing: create, edit, format, print– Presentation: create visual aids

Application Software• Examples

– Spreadsheet: organize data in rows, columns and perform calculation on data

– Database: organize data to allow easy access, retrieval and usage of data

– E-Mail: create, send, receive, forward, store, print, and delete email messages.

Network and the Internet• Network

– A collection of computers and devices connected together

– Often wirelessly via communication devices and transmission media

– Allows users to share resources – hardware, software, data, information

– Saves time and money

Types of Networks• Local Area Network (LAN)

– Connects computers and devices in a limited geographical area

• Wireless LAN (WLAN)– Similar to LAN but uses no physical wires. Connects

to a LAN.

• Wide Area Network (WAN) – Covers a large geographical area

The Internet• Worldwide collection of networks • Links businesses, governments, agencies,

educational and financial institutions, and individuals

• Internet Service Provide (ISP) – Access provider: individual/business that

provides access to Internet for free or fee.

World Wide Web (WWW)• A popular Internet service• Contains billions of documents called Web

pages• A web page

– Contains text, graphics, animation, audio, and video and links to other web pages

World Wide Web (WWW)• Website

– A collection of web pages– Can be accessed using a Web browser

• Web Address or Uniform Resource Locator (URL)– A unique address assigned to web page

Searching the Web• Primary use of the web

– Search for specific information

• Search engines – program that finds websites, web pages, images etc

related to a specific topic

• Subject Directory– Classifies web pages in organized set of categories or

groups such as sports, entertainments etc.

Computer Viruses and Malware• Computer Virus

– Damaging computer program – Alters the way computer works without

permission• Worm

– Computer program that copies itself repeatedly, using up resources

Computer Viruses and Malwares• Trojan horse (after Greek myth)

– Hides within or looks like a legit program– Certain actions trigger the Trojan horse

• Rootkit– Program that hides in a computer and allows

someone to remotely control the computer

Computer Viruses and Malware• Malware

– Virus, Worm, Trojan horse, rootkit• Antivirus programs

– Protects the computer from malware– Identifies and removes malware

Thanks