WHAT IS A COMPUTER

Overview and Characteristics of Computers

Overview As the twenty-first century ushers in the Information Age, we will experience new ways of living and working. The only way we can take advantage of and manage the vast amounts of available information is through the understanding of how computers work and through the ability to use computers. Most people believe that knowing how to use a computer is a basic skill necessary to succeed in the work world and to function effectively in society. This overview module will help you join the Information Age by learning the definition and characteristics of computers. Even if you do not have a home computer or use a computer at work, you have been using computers for some time. When you use an ATM, when you use a bank debit card, or when you order merchandise by phone; you are using a computer. You have also been exposed to many computer advertisements. The goal of this study guide is to help you become computer literate. In becoming computer literate, you will need to be aware of the importance of computers and be able to use them to accomplish tasks everyday. You probably have a good start toward computer literacy, but let’s take a closer look. Definition of a Computer The most obvious question you should ask is, What is a computer? A computer is an electronic device that operates under the control of a set of instructions that is stored in its memory unit. A computer accepts data from an input device and processes it into useful information which it displays on its output device. Actually, a computer is a collection of hardware and software components that help you accomplish many different tasks. Hardware consists of the computer itself, and any equipment connected to it. Software is the set of instructions that the computer follows in performing a task. We will explore hardware and software more in depth in the next module. A typical computer system is shown in the figure below. Classification of Computers Computers can be classified many different ways -- by size, by function, and/or by processing capacity. We will study the classification of computers by size. The size of a computer often determines its function and processing capacity. The size of computers varies widely from tiny to huge and is usually dictated by computing requirements. For example, it is clear that the IRS will have different requirements than those of a college student. The largest computers are supercomputers. They are the most powerful, the most expensive, and the fastest. They are capable of processing trillions of instructions per second. Examples of users of these computers are governmental agencies, such as the IRS, the National Weather Service, and the National Defense Agency. Also, they are used in the making of movies, space exploration, and the design of many other machines. The Cray supercomputer is nicknamed "Bubbles", because of its bubbling coolant liquids. Cray supercomputers, the first of which was invented by Seymour Cray, now maintain 75 percent of the supercomputer market. Supercomputers are used for tasks that require mammoth data manipulation. Large computers are called mainframes. Mainframe computers process data at very high rates of speed, measured in the millions of instructions per second. They are very expensive, costing millions of dollars in some cases. Mainframes are designed for multiple users and process vast amounts of data quickly. Banks, insurance companies, manufacturers, mail-order companies, and airlines are typical users. Mainframes are often ‘servers’-- computers that control the networks of computers for large companies like catalog merchandiser L. L. Bean. Microcomputers can be divided into two groups -- personal computers and workstations. Workstations are specialized computers that approach the speed of mainframes. Often microcomputers are connected to networks of other computers. The price of a microcomputer varies greatly from less than $1000 to several thousand dollars, depending on the capacity and features of the computer. Microcomputers make up the vast majority of computers. Another classification of computer is the notebook computer. A notebook computer can fit into a briefcase and weigh fewer than two pounds, yet it can compete with the microcomputer. A larger, heavier version is called a laptop computer. Notebooks generally cost more than microcomputers but can run most of the microcomputer software and are more versatile. Like other computers, notebook computers are getting faster, lighter, and more functional. The smallest computer is the handheld computer called a personal digital assistant or a PDA. PDAs are used to track appointments and shipments as well as names and addresses. PDAs are called pen-based computers because they utilize a pen-like stylus that accepts hand-written input directly on a touch-sensitive screen. You have probably noticed delivery employees using these. Speed, Reliability, Storage Capacity and Productivity Computers of all sizes have common characteristics -- speed, reliability, storage capacity, and productivity. Computers are the foundation of business, travel, and leisure life today. Computers provide the processing speed required by all facets of society. The quick service we expect at the bank, at the grocery store, on the stock exchange, and on the Internet are dependent on the speed of computers. Can you imagine our world without computers? Computers are extremely reliable as well. Most errors are caused by humans, not computers. Computers are capable of storing enormous amounts of data that must be located and retrieved very quickly. The capability to store and retrieve volumes of data is at the core of the Information Age.