THE PERIPHERALS OF COMPUTERS 6 PERIPHERAL DEVICES Answer these questions. a. Can you list at least three input and three output devices? b. Think about a normal week of yours. How many and what peripherals do you use? What for? buzzer: campanello coal: carbone to display: mostrare in conjunction with: in abbinamento a microwave oven: forno a microonde pattern: schema The origin of the word input dates back to 1753 when it was used with reference to money in the sense of sharing, or contribution. In 1902 it was first used with the meaning of supplying energy to a device or machine, and it was only used as a computing term, i.e. feeding data into a machine, in 1948. The word output was coined in 1839 from out+put and it was used as a technical term in the iron and coal trade until 1880. The verb is attested in the 14th century and the modern meaning of product dates back to 1858. 78 Peripheral devices, computer peripherals, or simply peripherals, are any kind of device used to enter information and instructions into a computer for processing and to deliver the output to a human user or to a machine controlled by a computer. They are usually divided into input devices and output devices. An input device converts incoming data and instructions into a pattern of electrical signals in binary code in order to make them comprehensible to a digital computer. It can send data to another device, but cannot receive data from another one. For example, a keyboard and a mouse can send data to the computer, but they cannot receive or reproduce information. Input devices can be manual or automated. Manual peripherals are input devices that allow the user to interact directly with the computer such as in the case of a keyboard, a mouse or a video capturing device. Automated input devices use methods of capturing and entering data directly without any human intervention. This mechanism, called direct data entry (DDE), is used when very large amounts of data need to be input quickly and accurately. The most common types of automated devices include sensors and different types of card readers. An output device translates digitised signals into a form that is understandable to the user. In other words, it reproduces or displays the results of the computer processing. It can receive data from another device, but it cannot send data. For example, a monitor can receive data from the computer, but cannot send information to it. There are manual output devices like a monitor or a printer, and control devices. Control devices are used to control processes in conjunction with sensor input devices. They convert the signals received by the computer into sounds, light, etc., as in the case of a microwave oven which has a buzzer that produces a sound when the food is cooked. Let s look at a practical example of how input and output devices work together. A keyboard sends electrical signals which are received by the computer as input. The signals are interpreted by the computer and displayed on the monitor as output. Then, the computer sends data to a printer, which will print data on a piece of paper as output. The data on the monitor, and any other type of virtual data, are called soft copy, while the printed ones are called hard copy because they are tangible and cannot be modified. There are some devices that can be both input and output (I/O) devices. They can both send to and receive data from another device. An example of I/O is the touch screen. Module 2 FLOWCHARTING