A “peripheral device” or “computer device” is a hardware component that is attached to a computer in order to expand its abilities and performing additional features. Computers are able to interact with its external world using the peripherals as mice, monitors, plotters, keyboards, and printers.
Peripheral means “additional but not essential”, so peripherals are not part of the essential computer as are the processor, and the memory. Some peripherals are mounted in the same case with the main part of the computer as are the hard disk drive or CD-ROM drive. If a peripheral device is disconnected, the computer will still be able to work. Other peripherals are outside the computer case, such as the printer and image scanner, attached by a wired or wireless connection.
Peripheral devices can also include other computers on a network system. A device can also refer to a non-physical item, such as a pseudo terminal, a RAM drive, or a network adapter.
Peripheral can be internal or external devices. It is important to have in mind, when selecting GIS software to ensure that it is compatible with any existing peripherals you use.
Most devices, whether peripheral or not, require a program called a device driver that acts as a translator, converting general commands from an application into specific commands that the device understands.