An input device is any device that provides input to a computer. There are dozens of possible input devices, but the two most common ones are a keyboard and mouse. Every key you press on the keyboard and every movement or click you make with the mouse sends a specific input signal to the computer. These commands allow you to open programs, type messages, drag objects, and perform many other functions on your computer.
Since the job of a computer is primarily to process input, computers are pretty useless without input devices. Just imagine how much fun you would have using your computer without a keyboard or mouse. Not very much. Therefore, input devices are a vital part of every computer system.
While most computers come with a keyboard and mouse, other input devices may also be used to send information to the computer. Some examples include joysticks, MIDI keyboards, microphones, scanners, digital cameras, webcams, card readers, UPC scanners, and scientific measuring equipment. All these devices send information to the computer and therefore are categorized as input devices. Peripherals that output data from the computer are called output devices.
On most computers, a keyboard is the primary text input device. (The mouse is also a primary input device but lacks the ability to easily transmit textual information.) The keyboard also contains certain standard function keys, such as the Escape key, tab and cursor movement keys, shift and control keys, and sometimes other manufacturer-customized keys.
The computer keyboard uses the same key arrangement as the mechanical and electronic typewriter keyboards that preceded the computer. The standard arrangement of alphabetic keys is known as the Qwerty (keyboard, its name deriving from the arrangement of the five keys at the upper left of the three rows of alphabetic keys. This arrangement, invented for one of the earliest mechanical typewriters, dates back to the 1870s. Another well-known key arrangement is the Dvorak system, which was designed to be easier to learn and use. The Dvorak keyboard was designed with the most common consonants on one side of the middle or home row and the vowels on the other side so that typing tends to alternate key strokes back and forth between hands. Although the Dvorak keyboard has never been widely used, it has adherents.
Because many keyboard users develop a cumulative trauma disorder, such as carpal tunnel syndrome, a number of ergonomic keyboards have been developed. Approaches include keyboards contoured to alleviate stress and foot-driven pedals for certain keys or keyboard functions.
What Are Output Devices?
Output devices are pieces of computer hardware that allow a computer system to communicate information to a user or another system. This information can be in any form, and includes sound, images, and even tactile experiences. Output devices can usually only be used to send data from the computer; items called input devices allow users and other systems to send data to the computer.
Some of the most common output devices allow computers to present information visually. The visual display unit called a monitor that can be found connected to almost every personal computer is the best example of this. Text, pictures, and other images are displayed on the monitor, allowing users to interact with computer programs and receive data. Video projectors are another type of output device. They function in a way similar to monitors, but display images over a much larger area. Computer printers are another type of output device that can be easily found. Printers allow the computer to produce documents, pictures, and images on paper through the use of inks and other dyes.
Audio output devices are also common. Computer speakers are the primary source of this form of output. They allow the computer to emit sounds that include music, audio tracks to digitized television shows, and even the voices of other users. Headphones also do the same thing, but are placed closer to the ears so that the sounds cannot be heard by others.
Computers can even communicate with users through the sense of touch. Refreshable Braille displays, or Braille terminals, allow computers to send information by way of raised dots that are “read” with the fingertips. Force feedback devices, or haptic devices, are sometimes built into joysticks and mice so that users can feel vibrations and pressure. Tactile output devices are less common than many other types, but can still be extremely important to users.
Rarely, output devices can also be input devices. A storage device such as a CD-RW drive is an excellent example of this. The computer uses it as an output device when it is writing information to a CD-ROM or other media that can be read by other computers. However, the computer uses it as an input device when reading information from a CD-ROM or other piece of storage media that has data written on it from another system.
In a computer, storage is the place where data is held in an electromagnetic or optical form for access by a computer processor. There are two general usages.
- Storage is frequently used to mean the devices and data connected to the computer through input/output operations that is hard disk and tape system and other forms of storage that don’t include computer memory and other in-computer storage. For the enterprise, the options for this kind of storage are much greater variety and expense than related to memory.
- In a more formal usage, storage has been divided into: (1)primary storage, which holds data in memory (sometimes call random access memory or RAM) and (2)secondary storage, which holds data on hard disks, tapes, and other devices requiring input/output operations.
- Types of Storage Devices:
(1) Floppy drive
(2) Super drive
(3) Zip Drive
(4) CD Burner
(5) DVD burner
(6) Hard Drive
(7) Flash drive
(8) Tape drive
(9) NAS – Netowork attachment storage
(10) SAN – Storage area network