Peripheral Management and Drivers
Peripherals
A peripheral is a device connected to a computer that is not part of the CPU or main memory. The processor does the computing and main memory holds the programs and data being worked on; every device attached around them, from a games controller to a projector, is a peripheral.
Input, output and storage
Peripherals are usually put into three groups:
| Type | What it does | Examples |
|---|---|---|
| Input | Sends data from the outside world into the computer | games controller, barcode reader at a till, graphics tablet |
| Output | Takes data out of the computer so it can be seen or used | projector, a robot arm moving into position, the rumble motor inside a games controller |
| Storage | Keeps data so it can be read back later | memory card from a camera, external DVD drive |
Storage peripherals are easy to overlook because nothing appears on a screen and you do not type into them, but a memory card reader is just as much a peripheral as a projector. Some devices do two jobs at once: a touchscreen shows you information and takes your taps, so it is both an output and an input device.
Many devices, all different
A computer may have lots of peripherals connected at the same time, made by different manufacturers and each working in its own way. One might send data in quick bursts, another in a slow trickle, and they do not all use the same type of connection. Data is being transferred constantly in both directions between the peripherals and the processor, so keeping track of which data belongs to which device is a job in itself. The operating system looks after this through peripheral management.
Peripherals are slow
Peripherals work at a fraction of the speed of the processor. A CPU can carry out billions of instructions every second, while a barcode reader only produces a fresh reading each time a packet is scanned. The processor would sit idle for most of that time if it simply waited, which is one reason data moving to and from peripherals has to be scheduled carefully.
Practise this
OCR GCSE Computer Science · Peripheral Management and Drivers