Chapter 5

Two Types Of Input

Input is any data or instructions entered into the memory of a computer. Two types of input are data and instructions. Data is a collection of unorganized items that can include words, numbers, pictures, sounds, and video. A user response is an instruction you issue to the computer by responding to a question posed by a computer program. Any hardware component that allows you to enter data, programs, commands, and user responses into a computer is an input device.

The Characteristics Of A Keyboard

The keyboard is an input device that contains keys you press to enter data into a computer. Desktop computer keyboards usually have from 101 to 105 keys, while keyboards for smaller computers contain fewer keys.

Identify Various Types Of Keyboards

A standard computer keyboard sometimes is called a QWERTY keyboard because of the layout of its typing area. An enhanced keyboard has 12 function keys along the top row, 2 ctrl keys, 2 alt keys, and a set of arrow and additional keys between the typing area and the numeric keypad. Cordless keyboards transmit data via infrared light waves. Keyboards for notebook and handheld computers usually have smaller and fewer keys than desktop computers. A portable keyboard is a full-sized keyboard you can attach to and remove from a handheld computer.

 How A Mouse Works

you move a mouse across a flat surface, the movement is translated into signals that are sent to the computer, and the pointer on the screen also moves. When you move the mouse to the right, the pointer moves to the right on the screen. For Windows users, the top of a mouse has at least two buttons and sometimes also a wheel. Generally, you use a mouse to move the pointer on the screen to an object and then press a button, or click, to perform a certain action on that object. Other operations you can perform using a mouse include right-click, double-click, drag, right-drag, rotate wheel, and press wheel button.

Scanners And Other Reading Devices Work

Scanners and optical readers can capture data from a source document, which is the original form of the data. A scanner is a light-sensing input device that reads printed text and graphics and then translates the results into a form a computer can use. One of the more popular scanners is a flatbed scanner, which works similarly to a copy machine except it creates a file of the document in memory instead of a paper copy. Many scanners include OCR software, which converts a scanned image into a text file that can be edited. An optical reader uses a light source to read characters, marks, and codes and converts them into digital data that a computer can process. Three types of optical readers are optical character recognition, optical mark recognition, and bar code scanner. Optical character recognition (OCR) is a technology that reads typewritten, computer printed, or handwritten characters from ordinary documents and translates the images into a form that the computer can understand. Optical mark recognition (OMR) devices read hand-drawn marks such as circles or rectangles. A bar code scanner uses laser beams to read bar codes, which are identification codes consisting of vertical lines and spaces of different widths. Another type of reader, called a magnetic-ink character recognition (MICR) reader, reads text printed with magnetized ink and is used almost exclusively by the banking industry.