What Is a Computer and What Does It Do? Computer: programmable, electronic device that accepts data, performs operations, presents the results, and can store the data or results Input—entering data into the computer Processing—performing operations on the data Output—presenting the results Storage—saving data, programs, or output for future use

What Is a Computer and What Does It Do? Cont’d

Data vs. Information Data = raw, unorganized facts Can be in the form of text, graphics, audio, or video Information = data that has been processed into a meaningful form Computers process data into information

The components of a computer 6 Primary components Input devices Processor Memory Output devices Storage devices Communication devices All the components are housed in a box called the system unit INPUT OUTPUT STORAGE COMMUNICATION MEMORY PROCESSOR SYSTEM UNIT- case containing the electronic components of the computer used to process data MOTHERBOARD main circuit board of the computer and has many components that attach to it PROCESSOR aka CPU interprets and carries out the basic instructions that operate a computer ALU performs the logical and arithmetic processes MEMORY RAM stores instructions waiting to be executed by the processor

Hardware The physical parts of a computer are collectively referred to as hardware Internal hardware: located inside the main box (system unit) of the computer External hardware: located outside the system unit and plug into connectors called ports located on the exterior of the system unit

Storage Devices Used to store instructions data and information when they are not being used for memory Disks Tape Mobile Storage DISKS magnetic that have to be formatted by dividing the disk into tracks and sectors such as a floppy or zip OPTICAL flat, round prtable disk made of plastic and written/read by a laser CDROM, CDR, CDRW, DVDROM, DVDR TAPEmagnetically coated robbon of plastic stores large amounts of data at a low cost MOBILE STORAGE USB, flash drive

Communication Devices Hardware component that allows a computer to send and receive data, instructions and information to and from 1 or more computers Communications occur over transmission media MEDIA cable, phone, radio, network, satelites

INPUT AND OUTPUT Hardware that allows you to enter data, programs or commands Keyboard Mouse Scanner Microphone Hardware that makes the information that was processed available for use Printers Display devices Speakers PRINTERS non impact and impact DD LCD, CRT monitors

Software The programs or instructions used to tell the computer hardware what to do System software: allows a computer to operate Operating system: the main system software program Boots the computer and launches programs etc. at the user’s direction Windows, Mac OS, Linux, etc.

Software Application software: performs specific tasks or applications Creating letters, budgets, etc. Managing inventory and customer databases Scheduling appointments Viewing Web pages Sending and receiving e-mail Designing homes Playing games And much, much more

Electrical Components Electrical components include: Motherboard Processor ALU CPU Memory Usually measured in kilobytes (1,000 bytes), megabytes (1 million) or gigabytes (1 billion) A byte is equal to one character

Computers to Fit Every Need Five basic categories Mobile devices Personal computers Midrange servers Mainframe computers Supercomputers

Mobile Devices Very small device with some type of built-in computing or Internet capability Typically based on cellular phones Smart phones can be used to access the Web and e-mail, take photos, play games, access calendars, and address books Smart watches can download information from the Internet, store data, play music files, etc.

Personal Computers Small computer system designed to be used by one person at a time; small enough to fit on a desktop, inside a briefcase Also called a microcomputer PC-compatible: evolved from the original IBM PC; typically runs the Windows operating system Macintosh: type of personal computer manufactured by Apple, uses the Mac OS operating system Can be desktop, notebook, tablet, or handheld computers

Desktop PCs Desktop PC: the complete computer system fits on or next to a desk; case styles include: Tower Desktop All-in-one

Midrange Servers Minicomputer or midrange computer: medium-sized computer used to host programs and data for a small network May consist of a collection of individual circuit boards called blades (blade servers)

Mainframe Computers Standard choice for large organizations, hospitals, universities, large businesses, banks, government offices Larger, more expensive, and more powerful than midrange servers; usually operate 24 hours a day Also called high-end servers or enterprise-class servers

Supercomputers Fastest, most expensive, most powerful type of computer Space exploration, missile guidance, satellites, weather forecast, oil exploration, scientific research, complex Web sites, decision support systems, 3D applications Commonly built by connecting hundreds of smaller computers, supercomputing cluster

Supercomputers, Cont’d

Computer Networks and the Internet Computer network: collection of hardware and other devices that are connected together so that users can share hardware, software, and data, as well as communicate with each other Network servers: manage resources on a network Clients: computers on a network that access resources through the network server Computer networks exist in many sizes and types

What Are the Internet and the World Wide Web? Internet: largest and most well-known computer network in the world Individuals connect to the Internet using an Internet service provider (ISP) Most common Internet activities: e-mail and accessing the World Wide Web (WWW) “Internet” refers to the physical structure of that network, the World Wide Web is one resource (a vast collection of Web pages) available through the Internet

Accessing a Network or the Internet Need a modem or network adapter to physically connect your computer to the network Software (often built into the operating system) allows you to log on to the network and access resources Many networks and Internet connections require a user ID and password to log on to the network

Accessing a Network or the Internet, Cont’d Internet addresses are used to access resources on the Internet IP address —numeric address that identifies computers (207.46.138.20) Domain name —text-based address that idenfies computers (microsoft.com) Uniform resource locator (URL) —identifies Web pages (http://www.pbskids.org) E-mail address —identifies people for e-mail exchange (jsmith@thomson.com)