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Devices Of Computer

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Devices of Computers

Computers perform the input, storage, processing, and output functions of the information system. In addition, computers and their devices need ways to communicate with one another. These devices are usually connected by electronic cables when located near each other. The factors that determine the reliability of an information system are the accuracy of data input, the convenience and quality of output, optimal use of storage devices, and the speed of a computer.

Accuracy of data input is important, and computers ensure that the results are correct by not making mistakes that people do. There are many types of input devices and deciding which one to use could save time and improve accuracy. Optical scanning, for example, is best used for printing questionnaires and retail tags. Optical scanning input devices include optical character recognition (OCR), which recognize certain printed characters. The OCR is an optimum way to read printed questionnaires because the optical character recognition senses marks made on forms. Relative to this, bar-code scanning is one of the most common optical scanning input devices. This device recognizes a bar code, which is the series of bars of different widths found on retail tags in stores. Another optimal scanner used is simply called a scanner; this device uses light to sense an image on paper. Any type of image can be scanned and businesses use scanners to transfer long documents and images into a computer. They can then be changed, stored, or used in screen or printed output. In addition to using a scanner, magnetic scanning is another type of scanning input device that recognizes magnetic patterns. An example of magnetic scanning is magnetic ink character recognition (MICR) which is an input technique used in the banking industry to process checks. The use of this technology in the banking industry is essential because of the high volume of checks that are processed everyday. Similar to scanning, there are other forms of input devices that are used for different purposes. For example, voice input devices uses voice recognition that aids in the use of telephone surveys. This input device is best used in this instance because voice input is the easiest form of communicating for most people. Software is trained to recognize the user's voice. Businesses found this most attractive because of a more user friendly system.

Relative to the accuracy of data input, the convenience and quality of output are just as important. An output device performs the opposite function of an input device. An output device converts data from an electronic form inside the computer to a form that can be used outside the computer. For example, a hand held computer uses a flat-panel screen to display output. The most common type of flat panel screen uses a liquid crystal display (LCD). A LCD screen is thin and lightweight and is best used for small hand held computers. In addition to a flat-panel screen, a laser printer is also used as an output device. A laser printer is a non-impact printer that prints by using technology similar to that of a copier. The image on a laser printer is made up of dots that produce an image like that of a color photograph. A color photograph is best printed on a laser printer but is very expensive. Similar to a laser printer, an ink-jet printer is also an excellent output device that is commonly used. An ink-jet printer is a non-impact printer that creates an image by spraying drops of ink on the paper. Ink-jet printers produce letter-quality output or, for example, a resume or memorandum. Most ink-jet printers can print in color , in black, and in white. Some printers can do more than just print computer output. Printers designed for high volumes of output are used mainly with multiple-user or large networked computer systems. These printers are used to create statistical reports or annual reports for businesses. High-volume printers can print more than 200 pages per minute and can cost over $100,000.

In a fast-paced world, different types of storage devices are optimal for different situations. Input data is stored in primary storage after it is received from an input device, and output data is stored before it is sent to an output device. Primary storage is composed of silicon chips containing millions of electronic circuits. The computer stores data in primary storage by turning some circuits on and others off, in a pattern that represents data. The primary storage device described is called random access memory (RAM). This means that data that is in any part of the primary storage can be accessed in any order. RAM is the main type of primary storage used with all computers. Similar to primary storage, secondary storage is also important storing information. Data from secondary storage and programs that are executing are stored in primary storage. In contrast to primary storage, secondary storage is not as volatile



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