Computer Peripherals

0.1.
Definition
This is a course on computer peripherals, so we have to begin by defining what is meant by
the term peripheral. A computer system consists of a number of functional components, the most
significant of which is the central processor unit or CPU. The central processor, whether a large
mainframe or minicomputer or even a small microprocessor-based personal computer, performs
its logic, memory access and computation operations at rates of millions of operations per second.
In order for this capability to be harnessed and applied to the real physical world of slow humans
like us the results of these processes must be slowed down, translated into words, images, or
control signals. It is the job of peripheral devices or peripherals to provide information to and
extract results from the central processor.
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Introduction
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0.2.
Classification
Peripheral devices are usually classified by their function:
(1)
Input devices such as keyboards, mice, bar-code scanners and digitisers.
(2)
Output devices like printers, plotters and displays.
(3)
Storage devices, which include floppy and hard disks, optical disks and
magnetic tape drives.
(4)
Multi-media devices and others.
Most peripherals would fall into one of the above categories, although some may span two
classes. We will not cover the multi-media devices and it will be covered in CE446: Multimedia
Systems Design. If you look at a PC that you can get for slightly above $1,000, you will get a list
of peripherals together with it. A basic PC will have a keyboard for input, a harddisk for storage
and as well as a CRT display or output printer. Most system nowadays will come complete with
a floppy disk drive, a CD ROM and some user also include backup devices such as diskette, tape
drives an zip drives.
There are other classes of peripheral devices which will not be covered here. These are the
range of A/D and D/A interfaces for control and instrumentation, cameras and frame grabbers for
screen capturing and the various communications interfaces like LAN and ISDN devices which
are more dealt with in courses on real-time systems and data communications respectively.