Computer and Internet Basics Unit A

What is a computer? A computer is a device for processing data. More precisely a computer is a device that accepts input, processes data, stores data, and produces output, all according to a series of stored instructions. A program is a set of instructions to perform a task.

A Computer is a device that accepts input processes data stores data produces output (all according to a series of stored instructions)

Computer System Peripherals Computer + input devices + output devices + storage devices

Computer System

Computer system consists of: Hardware includes the electronic and mechanical devices that process data. Examples: microprocessor, key board. Peripheral devices expand the computer’s input, output, and storage capabilities. Examples: Printers. Software: programs

Computer Network A computer network consists of two or more computers and other devices that are connected for the purpose of sharing data and programs.

LAN A LAN (local Area network) is a computer network that is located within a limited geographical area, such as a building or campus.

COMPUTER FUNCTIONS Computer Input is whatever is put into a computer system. Input can be supplied by a person, by the environment, or by another computer. Data refers to the symbols that represent facts, objects, and ideas.

COMPUTER FUNCTIONS Computer manipulate data in many ways, and we call this manipulation processing

COMPUTER FUNCTIONS The instructions that tell a computer how to carry out the processing tasks are referred to as a computer program. In a computer most processing takes place in the central processing unit (CPU) (also known as microprocessor) A computer stores data so that it will be available for processing. Memory is an area of a computer that temporarily holds data waiting to be processed, stored, or output. Storage is the area of a computer that holds data on a permanent basis when it is not immediately needed for processing.

Computer Functions Words, symbols, numbers, sound, pictures, program instructions Input Program calculates, sorts modifies data Uses microprocessor or CPU Process Results of processing Reports, graphs, documents, pictures Printer or monitor Output Memory is temporary holding area (RAM) Storage is permanent (disk) Store

Categorizing Computers Cost Usage Size Capability

Less Powerful Computers PC/microcomputer Workstations Handheld computer/PDA CD: video on PDA Videogame console Sony PlayStation®

Personal Computer A PC is designed to meet the computing needs of a person. It typically provides access to a wide variety of computing applications, such word processing, photo editing, e-mail, etc. There are four types: desktop, notebook computers, workstations, and video game console. Workstations are usually powerful desktop computers for special purposes.

Servers The purpose of a server is to serve the computers on a network by supplying them with data. A PC, workstation, mainframe or supercomputer can work as a server.

Mainframes A mainframe is a large and expensive computer capable of simultaneously processing data for hundreds or thousands of users. Mainframes are used by businesses, universities, or governments to provide centralize storage, processing and management of large amount of data.

Supercomputers A computer is a supercomputer if, at the time of construction, it is one of the fastest computers in the world. Supercomputers are used in complex tasks such as breaking codes or climate modeling. The CPU of a supercomputer contains thousands of microprocessors. http://www.top500.org

Computer System Peripherals Computer + input devices + output devices + storage devices

System Unit The system unit is the case that holds the power supply, storage devices, and the circuit boards, including the main circuit board (also called the “mother board”), which contains the microprocessor.

System Unit Power Supply Storage Devices Circuit Boards

Input/Output Devices Monitor Keyboard Mouse Modem Printer Speakers/sound card

Notes You can use a modem to establish an Internet connection using an standard telephone line. Computers have many types of storage devices that are used to store data when the power is turned off.

Storage Devices Floppy disk drive Hard disk drive CD-ROM drive DVD drive CD writer

Storage Devices A floppy disk drive is a storage device that reads data from and writes data to a floppy disks. A hard disk drive can store billions of characters of data. A CD-ROM drive is a storage device that uses that uses laser technology to read data that is permanently stored on data or audio CDs. A DVD drive can read data from CDs DVDs, or DVD movie discs.

Data vs. Information Data (symbols) used by computers Information (meaningful) used by people

Data Computers process and store data using the binary number system and several other codes designed expressly for electronic data. Binary number system has only two digits 0 and 1. Each 0 and 1 is a Bit. Byte (8 bits)

Files Collection of data on a storage medium Data file (passive) Executable file (active) Filename and extension Image.jpg Word.exe Resume.doc

Software Application Software is a set of computer programs that helps a person carry out a task. System Software is a set of computer programs that helps a computer carry out basic tasks.

System Software Helps the computer monitor itself in order to function efficiently Operating system Master controller of all computer activities Popular operating systems PCs: Microsoft Windows, Mac OS Handhelds: Windows CE and Palm OS Servers: Linux and UNIX CD video: windows interface

Computers that operate in essentially the same way are said to be compatible. Two of the most important factors that influence the compatibility of two computers are the microprocessor and the operating system. A platform consists of the underlying hardware and software of the computer system.

Platform Mac and PC compatibility is an issue Microprocessor + Operating system Mac and PC compatibility is an issue Apple computer = Mac platform Original IBM computer = Windows or PC platform Info web: Apple computers

Designed to carry out a particular task Application Software Microsoft Excel Microsoft PowerPoint Designed to carry out a particular task

Internet Basics (Cyberspace) Internet is a collection of local, regional, national and international computer networks that are linked together to exchange data and distribute processing tasks. Infoweb: cyberspace Infoweb: internet resources

Internet Terminology The Internet backbone defines main Internet routes route= telecommunication link Constructed and maintained by major telecommunications companies. TCP/IP is a standard set of rules for electronically addressing and transmitting data. Transmission Control Protocol/ Internet Protocol

Internet Backbone

Internet Terminology IP Address: unique number for each Internet computer Packets: small chunks of data ready to travel the Internet Router: helps send along the packets to correct destination CD screentour: web sites provides files

Internet Resources Internet Telephony Usenet E-commerce Instant Messaging Web Sites E-mail Internet Radio Download Or Upload Chat Groups

Modem Internet Connections Dial-up connection via modem requires a modem, which converts your computer’s digital signals into a type of signal that can travel over phone lines. The maximum speed is 56Kbps, or 56,000 bits per second. E-mail, E-commerce, and chat. Infoweb: national ISPs Lab: making a dialup connection CD video: computer modems

Faster Internet Connections ISDN (Integrated Services Digital Network) provides data transfer speeds of either 64K or 128K. Always-on and expensive DSL (Digital Subscriber Line) is a generic name for a family of high –speed Internet links, including ADSL, SDSL, and DSL lite. Up to 125 times faster than dialup Both ISDN and DSL connections require proximity to a telephone switching station.

Internet Service Provider (ISP) An ISP is a company that maintains Internet computers and telecommunications equipment in order to provide Internet access to businesses, organizations and individuals User ID and password required Email account monthly fee Should have local access telephone numbers

World Wide Web Basics The web (or World Wide Web) is a collection of files that are interconnected through of hypertext. Hypertext: text, video, pictures. A Web pages is a collection of hypertext documents and links (or hyperlinks). A link is a related document. A web site is a collection of web pages with an Internet address. A Web server is a computer that stores and distributes web pages. Infoweb: hypertext

World Wide Web Basics http://www.cnn.com/showbiz/movies.htm URL (uniform resource locator) is the internet address of a web site. HTTP ( Hypertext Transfer Protocol) is the communications standard that is used to transport web documents over the Internet. HTML (Hypertext Markup Language) is a language to create web pages. .htm or .html file extension Document name and filename extension Folder name Web server protocol standard http://www.cnn.com/showbiz/movies.htm

Browsers and Search Engines A browser is a software program that runs on your computer and helps you access web page. A search engine refers to a web site that provides a variety of tools to help you find information on the Web. Infoweb: browser Lab: browsing and searching Microsoft Internet Explorer® and Netscape Navigator®

Computer and Internet Basics End