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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