Know your computer

Know Your ComputerKnow Your Computer
Presentation developed by
NCST
for Intel® Teach to the Future Training

OverviewOverview
• IT and the information processing cycle
• What are computers?
• Kinds of computers – mainframes,
minicomputers, and microcomputers or
personal computers
• Components of a computer – hardware,
software

• Hardware – CPU, storage devices,
input devices, display and output
devices
• Software – Operating system and
programs
• Applications – Word processing,
desktop publishing, spreadsheets,
databases, network, and multimedia
OverviewOverview….contd.….contd.

What Can IT do?What Can IT do?
• The tasks that are being handled through
Information Technology or IT for short, are
increasing day by day.
• IT can do at least three things:
– Process raw data into useful information
– Recycle processed information and reuse it for
other purposes
– Package information in a new form that is easier
to understand.

Information processing cycleInformation processing cycle
• Information processing is a small step
in the larger cycle: input, processing,
output, storage and retrieval, and
distribution and communication.
• The computer is at the very heart of
Information technology. Computer
hardware and software are used in
every one of these steps.

What are ComputersWhat are Computers
• Computers are electronic devices that
are capable of processing
data/information given in the form of
numbers, words, pictures, and even
sounds.
• They can be programmed (given
instructions) to carry out various kinds
of information processing jobs.

What are Computers …What are Computers …
• Various kinds of jobs that are done using
computers:
– Scientific computations
– Keeping track of information -- Banking, Railways
or Airlines Reservations
– Preparation of documents and multimedia
presentations
– Simulation of real or imaginary world scenes –
Virtual Reality, Computer Games
– Storing and sharing information – World Wide
Web

Different Kinds of ComputersDifferent Kinds of Computers
• Depending on the size and capacity,
computers are classified into three
types:
– Mainframe computers
– Minicomputers
– Microcomputers or Personal computers.

Mainframe ComputersMainframe Computers
• Large and powerful computers that are used by
many people (users) at the same time; typically
installed in large organizations.
• Located in a central place and accessed by
users via computer terminals or other
computers placed at different locations and
connected to the mainframe computer.
• Supercomputers: Extremely powerful
mainframe computers used in scientific and
engineering applications.

MinicomputersMinicomputers
• Minicomputers are medium sized
computers -- Between Mainframe
computers and Microcomputers
• Are also used by many users at the
same time
• Used in small organizations.

What is a SERVER?What is a SERVER?
• Until recently, the big computers were called
as mainframes and the smaller ones as
minicomputers.
• As computer networks have begun to
dominate, the mainframe has just become
one of many computers. However, because
of its large size, it is often the one where
other computers on the network look for data
and also the one that runs powerful software
and serves other computers.
• Hence the term Server.

Microcomputers or PersonalMicrocomputers or Personal
ComputersComputers
• Small computers that fit on your desk; meant to
be used by one user (at a time)
• Workstation: A microcomputer with enhanced
graphics and communication capabilities
• Laptop: A microcomputer that is small enough
to fit in a briefcase.
• Network computer: A small microcomputer with
no built-in disk storage, but makes use of larger
computers of the company’s network or the
Internet through a browser

Microcomputers …Microcomputers …
• With the advent of smaller and faster
computer chips and low-cost-high-
capacity storage devices, present day
personal computers are becoming more
and more powerful, with capabilities
comparable to the mainframe
computers of olden days.

Components of a ComputerComponents of a Computer
• The components of a computer are classified
into the two main categories – hardware and
software
• Hardware: The mechanical and electronic
parts that perform the various tasks of the
computer
• Software: The programs that tell the hardware
what tasks are to be done and how.

Hardware componentsHardware components
• The hardware of a typical computer
system, irrespective of its size, consists
of the following components:
– Central Processing Unit -- CPU
– Memory and Storage devices
– Input devices
– Display and output devices.

Central Processing Unit (CPU)Central Processing Unit (CPU)
• The CPU performs arithmetic and logical calculations and
controls the operations of other parts of the computer.
• The CPU cabinet, houses the processing components
• The CPU may be a single silicon chip or a series of chips. A
chip contains thousands of electronic switching circuits.
• Each circuit can be set ON or OFF and it represents a bit whose
value can be 1 or 0.Computer stores and processes
data/information in terms of these bits.

Computer speedComputer speed
• A basic arithmetic operation like addition of
two numbers is a single computer instruction.
An instruction is executed in one or more
clock cycles.
• Computer speeds are measured in
megahertz or millions of clock cycles per
second.
• Typical speeds of present day
microprocessors are few hundred megahertz.
• A super computer can do trillions of arithmetic
and logical operations per second.

Data representation and sizeData representation and size
• Typical representation of various data:
– A character is represented by one byte
– An integer is represented by 4 bytes.
– A floating point is represented by 4 or 8 bytes.
– The size of data to represent a color picture
(image) covering one fourth of your computer
screen may be a few MB.
• 1 byte = 8 bits
• 1 KB (kilobytes) = 210
that is about one thousand
bytes
• 1 MB (megabytes) = 210
KB
• 1 GB (gigabytes) = 210
MB.

Memory and Storage DevicesMemory and Storage Devices
• Computer Memory, also known as internal storage
device, consists of silicon chips that are directly
linked to the CPU.
• The memory and storage devices are located in the
CPU cabinet
• There are two kinds of memory
– Read-Only Memory or ROM: Contains basic
instructions of the computer stored permanently.
– Random-Access Memory or RAM: In RAM the
computer copies and keeps temporarily user’s programs
and data, in part or full, at the time of execution.
• The size of RAM is important for speedy execution of
large programs. For a personal computer, typical size
of RAM is 64 or 128 MB.

Memory and Storage Devices …Memory and Storage Devices …
• In order to store user programs and data
permanently or as long as user wants,
computers use (external) storage devices.
• The common storage devices used in
personal computers are:
– Hard disks: These are disks, fixed inside the
cabinet, used for storing (read and write) very
large amounts of information. Typical sizes are
about 20 or 40 GB.

Storage Devices …..Storage Devices …..
– Floppy disks: Used by means of floppy disk
drive(s) attached to the computer. Floppy
disks in normal use today store about 800
KB or 1.4 MB of data – read and write.
– CD-ROMs: Used by means of CD-ROM
drive(s). Standard capacity is about 600
MB of data – read only.
• While a hard disc is fixed to the computer,
floppy disks and CD-ROMs are removable
and can be used to transfer data.

Input DevicesInput Devices
• Input devices are used by the user to enter data,
commands and programs to the computer. Most
common devices are:
– Keyboard: Used to enter text data.
– Mouse: Used to point and click at any
location on the computer’s video display
screen. Normally a mouse will have two
or three buttons.
– Trackball: Replaces the mouse on laptops.

Input devices …Input devices …
• Other input devices
– Joystick: Similar functionality as mouse
– Light pen: Used to point or sketch directly
on the screen.
– Scanners: To scan (input) images
– Digital cameras: To capture pictures
directly.
– Voice recognition systems: These accept
spoken words as input.

Display and Output DevicesDisplay and Output Devices
• Monitor or Display: It is the main output device of a
computer. It displays text as well as pictures in black
and white or color.
– The monitor screen consists of an array of tiny
dots called pixels (picture elements). Typical sizes
of this array of pixels are 640 by 480 or 800 by
600 or 1024 by 768. This is also referred as the
resolution.
– Each pixel can be independently illuminated by a
color. The number of colors displayable on a
monitor can be 16 or 256 or 216
(high color) or 224
(true color).
– Resolution and number of colors can be set by
user.

Output Devices …Output Devices …
• Printer: Another output device to which the
computer can directly send the data to obtain
hard copy printouts of the results.
– Laser printer: Commonly used printer. In
general it will be black and white. There are
also color laser printers.
– Other types of printers: Ink-jet printer, Dot-
matrix printer.

ModemModem
• A device used to link two computers via
(analogue) telephone lines.
• It converts digital signals into analogue
signals and vice-versa.

Computer SoftwareComputer Software
• Computer software can be classified
into following categories:
– Operating system
– User programs
– Application programs
Computer Hardware
Operating System
Application
Programs
User
Programs
User

Operating SystemOperating System
• Operating system (OS) is the basic software
responsible for interacting with the hardware.
• It is the foundation on which user programs
and application programs are built.
• It helps the user to enter programs or data,
store them in files and execute programs.
• Two popular operating systems in use today
are
– Unix – for mainframes and minicomputers.
– Microsoft Windows – for personal
computers.

ProgramsPrograms
• A program is a sequence of commands written
in a computer programming language that
specifies a task the computer will perform.
• Some of the computer programming languages
are:
– FORTRAN, COBOL, BASIC, C, C++, Java
• User Programs: Written by users or
programmers for themselves or for their
organization.

Application ProgramsApplication Programs
• Computers are increasingly being used in
almost every activity - business, industry,
commerce, health, education, entertainment,
sports, etc.
• Application programs is the catch-all name for
all programs that are used for carrying out
specific tasks - office document creation, pay
roll processing, …
• We shall discuss a few of the highly popular
application programs

Word processingWord processing
• A word processor is an application program
that supports the basic tasks of entering,
editing, formatting and archiving a text
document.
• Microsoft Word includes a number of powerful
features, such as word wrap, find and
replace, tables, columns, spell check,
grammar and style analysis and mail merge.

Desktop PublishingDesktop Publishing
• Provides functions that until ten years back
were only possible to be carried out at a good
printing house.
• A basic function is page layout, the ability to
place text, diagrams and images on a page in
any way, easily and accurately.
• Other functions include a variety of fonts,
styles, content and index generation, etc.

SpreadsheetsSpreadsheets
• A spreadsheet application program is used to
enter numeric data in tabular format, along
with row/column labels and formulae that can
be combined to solve a variety of business
numeric problems.
• Spreadsheet applications also include
facilities for drawing charts, graphs, etc. from
tabulated data.

DatabasesDatabases
• Database application programs are used
when very large amounts of data are to be
stored in a structured manner, maintaining
various relationships among the data - for
example, information of all employees in a
company.
• A very powerful feature is the ability to rapidly
answer a variety of queries from the user
about the data in the database.

NetworkNetwork
• Network applications are programs that
enable us to communicate with and use
facilities of remote computers.
• These applications have proliferated with the
spread of the Internet and the introduction of
the WWW.
• Commonly used programs are - E-Mail,
Newsgroups, Chat, Games, File transfer,...

MultimediaMultimedia
• It all began with games, now it is dynamic
web pages, interactive courseware and
catalogues with sound and video - multimedia
application programs enable us to create
exciting content.
• These programs include facilities to create,
edit and render on the screen, text, pictures,
sound, animation, video and 3D graphics

Further ReadingFurther Reading
1. R. Carter, The Information Technology
Handbook, Heinemann Professional
Publishing Ltd, London, 1987.
2. P. Scharf and J. C. McNichols,
Understanding the Computer Age, Hayden
Book Company, New Jersey, 1994.
3. Microsoft®
Encarta®
Encyclopedia 2000 CD-
ROM, India Edition, 2000.

Know your computer

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