Computer

WHAT IS A COMPUTER AND WHAT DOES IT DO? 

A computer is a programmable electronic device that accepts input; performs processing operations; outputs the results; and provides storage for data, programs, or output when needed. Most computers today also have communications capabilities. 

This progression of input, processing, output, and storage is sometimes called the information processing cycle. Data is the raw, unorganized facts that are input into the computer to be processed. Data that the computer has processed into a useful form is called information. Data can exist in many forms, representing text, graphics, audio, and video. One of the first calculating devices was the abacus. Early computing devices that predate today’s computers include the slide rule, the mechanical calculator, and Dr. Herman Hollerith’s Punch Card Tabulating Machine and Sorter. First-generation computers, such as ENIAC and UNIVAC, were powered by vacuum tubes; second-generation computers used transistors; and third-generation computers were possible because of the invention of the integrated circuit (IC). Today’s fourth-generation computers use microprocessors and are frequently connected to the Internet and other networks. Some people believe that fifthgeneration computers will likely be based on artificial intelligence. A computer is made up of hardware (the actual physical equipment that makes up the computer system) and software (the computer’s programs). Common hardware components include the keyboard and mouse (input devices), the CPU (a processing device), monitors/display screens and printers (output devices), and storage devices and storage media (such as CDs, DVD drives, hard drives, USB flash drives, and flash memory cards). Most computers today also include a modem, network adapter, or other type of communications device to allow users to connect to the Internet or other network. All computers need system software, namely an operating system (usually Windows, Mac OS, or Linux), to function. The operating system assists with the boot process, and then controls the operation of the computer, such as to allow users to run other types of software and to manage their files. Most software programs today use a variety of graphical objects that are selected to tell the computer what to do. The basic workspace for Windows’ users is the Windows desktop. Application software consists of programs designed to allow people to perform specific tasks or applications, such as word processing, Web browsing, photo touch-up, and so on. Software programs are written using a programming language. Programs are written by programmers; computer users are the people who use computers to perform tasks or obtain information.

COMPUTERS TO FIT EVERY NEED

 Embedded computers are built into products (such as cars and household appliances) to give them added functionality. Mobile devices are small devices with computing or Internet capabilities; a mobile device based on a mobile phone is called a smartphone. Small computers used by individuals at home or work are called personal computers (PCs) or microcomputers. Most personal computers today are either desktop computers or portable computers (notebook computers, laptop computers, tablet computers, and netbooks) and typically conform to either the PC-compatible or Mac standard. Tablet computers come in both slate tablet and convertible tablet formats. Thin clients are designed solely to access a network; Internet appliances are designed specifically for accessing the Internet and e-mail. Medium-sized computers, or midrange servers, are used in many businesses to host data and programs to be accessed via the company network. A growing trend is virtualization—creating separate virtual environments on a single server that act as separate servers. The powerful computers used by most large businesses and organizations to perform the information processing necessary for day-to-day operations are called mainframe computers. The very largest, most powerful computers, which typically run one application at a time, are supercomputers. A group of numerous smaller computers connected together to act as a single supercomputer is a supercomputing cluster. 

COMPUTER NETWORKS AND THE INTERNET 

Computer networks are used to connect individual computers and related devices so that users can share hardware, software, and data as well as communicate with one another. The Internet is a worldwide collection of networks. Typically, individual users connect to the Internet by connecting to computers belonging to an Internet service provider (ISP)—a company that provides Internet access, usually for a fee. One resource available through the Internet is the World Wide Web (WWW)—an enormous collection of Web pages located on Web servers. The starting page for a Web site (a related group of Web pages) is called the home page for that site. Web pages are viewed with a Web browser, are connected with hyperlinks, and can be used for many helpful activities. To access a computer network, you need some type of modem or network adapter. To access the Internet, an Internet service provider (ISP) is also used. Internet addresses are used to identify resources on the Internet and include numerical IP addresses and text-based domain names (used to identify computers), Uniform Resource Locators or URLs (used to identify Web pages), and e-mail addresses (a combination of a username and domain name that is used to send an individual e-mail messages). Web pages are displayed by clicking hyperlinks or by typing appropriate URLs in the browser’s Address bar. Favorites/Bookmarks and the History list can be used to redisplay a previously visited Web page and search sites can be used to locate Web pages matching specified criteria. Electronic mail (e-mail) is used to send electronic messages over the Internet. 

COMPUTERS AND SOCIETY 

Computers and devices based on related technology have become indispensable tools for modern life, making ordinary tasks easier and quicker than ever before and helping make today’s worker more productive than ever before. In addition to the benefits, however, there are many risks and societal implications related to our heavy use of the Internet and the vast amount of information available through the Internet. Issues include privacy and security risks and concerns (such as malware, identity theft, phishing, and spam), the differences in online and offline communications, the anonymity factor, and the amount of unreliable information that can be found on the Internet.