Any of the devices which connect to the CPU and exchange information under the CPU's control. Peripherals include all of the computer's input and output devices. A peripheral (truncation of peripheral device) is any computer device that is not part of the essential computer (the processor, memory, and data paths) but is situated relatively close by. Some peripherals are mounted in the same case with the main part of the computer, as are the hard disk drive, CD-ROM drive, and NIC. Other peripherals are outside the computer case, such as the printer and image scanner, attached by a wired or wireless connection.