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Chapter One
Introduction to Computer
Computer
A computer is an electronic device, operating under the control of instructions stored
in its own memory that can accept data (input), process the data according to specified
rules, produce information (output), and store the information for future use1
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Hardware:
Computer hardware is the collection of physical elements that constitutes a computer
system
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all of
which are physical objects that can be touched
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Microsoft Office 2013 Introductory
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IT3
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tutorialspoint
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htm
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http://en
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org/wiki/Computer_hardware
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Input Devices
Input device is any peripheral (piece of computer hardware equipment to provide data
and control signals to an information processing system such as a computer or other
information appliance
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Most common are keyboard and mouse

Example of Input Devices:1
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Touch screen
7
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Graphics Tablets
13
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Barcode reader
19
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Mouse (pointing device)
5
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MIDI keyboard
11
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Microphone
17
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Electronic Whiteboard

3
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Webcam
9
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Pen Input
15
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Joystick
21
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Generally standard Keyboard
has 104 keys
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It is responsible for all functions and processes
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The CPU is comprised of three main parts :
* Arithmetic Logic Unit (ALU): Executes all arithmetic and logical operations
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Logical operation like compare numbers, letters, or special characters
* Control Unit (CU): controls and co-ordinates computer components
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Read the code for the next instruction to be executed
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Increment the program counter so it points to the next instruction
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Read whatever data the instruction requires from cells in memory
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Provide the necessary data to an ALU or register
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If the instruction requires an ALU or specialized hardware to complete, instruct
the hardware to perform the requested operation
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Primary Memory:1
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It is volatile in nature, which means
that data will be erased once supply to the storage device is turned off
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RAM is considered "random access" because you can access any memory
cell directly if you know the row and column that intersect at that cell
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ROM (Read Only Memory): ROM is a permanent form of storage
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ROM devices
do not allow data stored on them to be modified
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Hard drive (HD): A hard disk is part of a unit, often called a "disk drive," "hard drive," or "hard
disk drive," that store and provides relatively quick access to large amounts of data on an
electromagnetically charged surface or set of surfaces
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Optical Disk: an optical disc drive (ODD) is a disk drive that uses laser light as part of the process
of reading or writing data to or from optical discs
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Compact discs,
DVDs, and Blu-ray discs are common types of optical media which can be read and recorded by
such drives
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There are three main types of optical media: CD,
DVD, and Blu-ray disc
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4 GB of data
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This storage capacity is a clear advantage over the floppy disk storage media (a
magnetic media), which only has a capacity of 1
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3

3
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A Flash disks have no mechanical platters or access
arms, but the term "disk" is used because the data are accessed as if they were on a hard drive
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Output devices
An output device is any piece of computer hardware equipment used to communicate
the results of data processing carried out by an information processing system (such
as a computer) which converts the electronically generated information into humanreadable form
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Monitor
3
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Plotters
7
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LCD Projection Panels
4
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Speaker(s)

Note Basic types of monitors are a
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B
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c
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Printer types: 1-Laser Printer
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3-Dot Matrix Printer

4

Software
Software is a generic term for organized collections of computer data and instructions,
often broken into two major categories: system software that provides the basic nontask-specific functions of the computer, and application software which is used by
users to accomplish specific tasks
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System software is responsible for controlling, integrating, and managing the
individual hardware components of a computer system so that other software and
the users of the system see it as a functional unit without having to be concerned
with the low-level details such as transferring data from memory to disk, or
rendering text onto a display
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B
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Application software may consist of a single program, such
as an image viewer; a small collection of programs (often called a software
package) that work closely together to accomplish a task, such as a spreadsheet or
text processing system; a larger collection (often called a software suite) of related
but independent programs and packages that have a common user interface or
shared data format, such as Microsoft Office, which consists of closely integrated
word processor, spreadsheet, database, etc
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Comparison Application Software and System Software
System Software
Computer software, or just software is a
general term primarily used for digitally stored
data such as computer programs and other
kinds of information read and written by
computers
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Example:

Interaction:

Dependency:

1) Microsoft Windows
2) Linux
3) Unix
4) Mac OSX
5) DOS
Generally, users do not interact with system
software as it works in the background
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5

Application Software
Application software, also known as an
applicati
obvious difference is that tablet computers don't have keyboards or touchpads
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Tablet computers are mostly
designed for consuming media, and they are optimized for tasks like web
browsing, watching videos, reading e-books, and playing games
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However, the convenience of a tablet computer means
that it may be ideal as a second computer
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They are basically small
tablet computers, and they can be used for web browsing, watching videos,
reading e-books, playing games and more
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So data means "unstructured facts and figures that have the least impact on the typical
manager
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Information thus paints a bigger picture; it is data with
relevance and purpose
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Essentially information is found "in
answers to questions that begin with such words as who, what, where, when, and how
many"
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The knowledge possessed by each individual is a product of his
experience, and encompasses the norms by which he evaluates new inputs from his
surroundings
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Data: symbols
2
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Knowledge: application of data and information; answers "how" questions
4
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We need to understand that processing data produced Information and process
Information produces Knowledge and so on
Characteristics of Computer
Speed, accuracy, diligence, storage capability and versatility are some of the key
characteristics of a computer
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Some calculations that would have taken hours and days to
complete otherwise, can be completed in a few seconds using the computer
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• Accuracy: Computer provides a high degree of accuracy
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• Diligence: When used for a longer period of time, the computer does not get tired or
fatigued
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• Storage Capability: Large volumes of data and information can be stored in the
computer and also retrieved whenever required
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Secondary storage devices like
floppy disk and compact disk can store a large amount of data permanently
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It can perform different types of tasks
with the same ease
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Computers have several limitations too
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9

Computer cannot do any work without instructions from the user
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Computer Viruses*
Viruses: A virus is a small piece of software that piggybacks on real programs
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Each time the spreadsheet program runs, the virus runs, too, and it has the
chance to reproduce (by attaching to other programs) or wreak havoc
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Some e-mail viruses don't even require
a double-click -- they launch when you view the infected message in the
preview pane of your e-mail software [source: Johnson]
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The program claims to
do one thing (it may claim to be a game) but instead does damage when you
run it (it may erase your hard disk)
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•Worms: A worm is a small piece of software that uses computer networks and security
holes to replicate itself
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It copies itself to the new machine
using the security hole, and then starts replicating from there, as well
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Update it and use it
regularly
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This will protect your system by
checking for viruses each time you run an executable file
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This includes packaged software that you buy from the store
as well as any program you might download from the Internet
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 Make sure you back up your data (documents, bookmark files, important email
messages, etc
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*http://computer
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com/virus
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us-cert

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