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Main » 2013 » August » 11
NETWORKS
Definitions: An Interconnected collection of autonomous processors. A Network is a group of
two or more computers connected to each other by a cable, over telephone lines or through
wireless communication. When you are connected to a network, you can share resources on your
computer such as documents, programs, printers, modems and use other resources from other
computer. The key idea of a Network is that users need equal access to resources such as data,
but they do not necessarily have to have equal computing power.
LANs, WANs and ‘Client Server” concepts are perhaps the most important trend in modern
computing.
There are two types of Networks
. LOCAL AREA NETWORK (LAN)
. WIDE AREA NETWORK (WAN)
LOCAL AREA NETWORK (LAN)
Definition: A network of computers located in a single building or an a single site.
A LAN may also
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Date:
08.11.2013
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WHAT IS COMPUTER?
A Computer is a device or set of devices that work under the control of a stored program,
automatically accepts and processes data to provide information.
. Automatic: it carries out instructions with minimum human intervention
. Re-programmable: it stores instruction (the program)
. A data processor: it carries out operations on data (numbers or words) made up of a
combination of digits to produce information.
Data is the name given to facts. Information is the meaningful data that is relevant, accurate, up
to date and can be used to make decisions.
A computer accepts and then processes input data according to the instructions it is given. The
elements of any sort of processing are INPUT, PROCESSING, STORAGE, and OUTPUT that
can be depicted as shown in the following diagram.
A Computer operations are performed according to programmed logical and arithmet
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HARDWARE
Hardware is the various physical components that comprise a computer system, as opposed to
the non-tangible software elements. Most of these physical components are physically separated
from the peripheral to the main circuitry that does the arithmetical and logical processing but
they are the most familiar bits of a computer.
2.1 COMPUTER DEVICES
A computer consists of several interconnected devices or components. They are five basic
components, namely, central processing unit, primary storage, secondary storage, input devices,
and output devices. This physical equipment that make up a computer is called hardware.
Secondary storage, input and output devices are often called peripheral equipment. The CPU and
primary storage contain electronic circuits that store and process data or program instruction. The
circuits are formed from place of silicon which is non-metal elem
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BENEFITS OF COMPUTER TO THE SOCIETY.
Although data processing either Manual or electronic have the same principle, but the difference
can still be explained as follows: -
ACCURACY of information is improved: The computers are generally accurate, whereas
humans are prone to error (errors in the input of data). Although there can be software error
(error in the programs) and hardware package errors (faults or breakdown in the equipment
itself).
The VOLUME of information to be processed is increased. As business grows and becomes
more complex, their data processing requirements increase in volume and complexity too.
Hence, electronic data processing is always employed to ease the demands on their workforce.
The SPEED at which information becomes available is higher: computers can process data much
more quickly than a human. This means that a computer can produce more timely informat
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INPUT DEVICES
These accept input data/programmes for processing converting if necessary into a form which
the computer can understand and operate on. Input is a labour intensive process, typically
involving the keying in of data using a keyboard. In many cases, transcription the process of
inputting data by keyboard so that it can be converted into the electronic pulses on which the
computer circuitry operate is avoided by a process of data capture, where data is recorded in such
a way as to be directly convertible into a machine sensible form without any human intervention.
In many situations, data capture or transcription occurs far away from the main computer and
data has to be transmitted to where it is to be processed.
Examples of Input device are:
. The Keyboard
. The Visual Display Unit (VDU)
. Mouse
. Trackball
. Document Reading Devices
http:/
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PRIMARY STORAGE
Primary storage is also called internal storage or memory. It is used to store programs and data
currently being processed by CPU. Primary storage circuits like light bulbs need electricity to
stay on. If the power to the computer is turned off, all the circuits will turn off and all data in
primary storage will be lost. When computer is turned back on the data will not reappear. The
data is lost forever. Because of this characteristics primary storage is called volatile storage. This
type of primary storage is called RANDOM ACCESS MEMORY or RAM. RAM is the main
type of primary storage used with computers and it is volatile.
ROM – Many computers have another type of primary storage called ROM – Read Only
Memory. ROM is non-volatile storage. This means that when the power to the computer is
turned off, the content of the ROM is not lost. ROM can store preset programs that
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