Intro Computers in 40 Characters

Engr. Athar Baig
Lecturer
Electronics Engineering Department
University of Chakwal
athar.baig@uoc.edu.pk
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Computer Science
Introducing Computer Systems
Introduction to Computers

Lecture Outline
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 History of Computers
 Generations of Computers
 Introduction to Computer
 Parts and functionality of a Computer
 Computer Software

History of Computer Systems
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 The first counting device was used by
the primitive people. They used sticks,
stones and bones as counting tools. As
human mind and technology improved
with time more computing devices were
developed.

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Abacus
 The history of computer begins with
the birth of abacus which is believed
to be the first computer. It is said that
Chinese invented Abacus around
4,000 years ago.
 It was a wooden rack which has
metal rods with beads mounted on
them. The beads were moved by the
abacus operator according to some
rules to perform arithmetic
calculations. Abacus is still used in
some countries like China, Russia
and Japan.

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Napier's Bones
 It was a manually-operated
calculating device which was
invented by John Napier (1550-
1617).
 In this calculating tool, he used 9
different bones marked with
numbers to multiply and divide.
So, the tool became known as
"Napier's Bones. It was also the
first machine to use the decimal
point.

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Pascaline
 Pascaline is also known as Arithmetic
Machine or Adding Machine. It was
invented between 1642 and 1644 by a
French mathematician-philosopher
Biaise Pascal. It is believed that it was
the first mechanical and automatic
calculator.
 Pascal invented this machine to help
his father, a tax accountant. It could
only perform addition and subtraction. It
was a wooden box with a series of
gears and wheels. When a wheel is
rotated one revolution, it rotates the
neighboring wheel. A series of windows

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Stepped Reckoner or Leibnitz wheel
 It was developed by a German
mathematician-philosopher Gottfried
Wilhelm Leibnitz in 1673. He
improved Pascal's invention to
develop this machine. It was a digital
mechanical calculator which was
called the stepped reckoner as
instead of gears it was made of
fluted drums.

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Difference Engine
 In the early 1820s, it was designed
by Charles Babbage who is known
as "Father of Modern Computer". It
was a mechanical computer which
could perform simple calculations. It
was a steam driven calculating
machine designed to solve tables of
numbers like logarithm tables.

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Analytical Engine
 This calculating machine was also
developed by Charles Babbage in
1830. It was a mechanical computer
that used punch-cards as input. It
was capable of solving any
mathematical problem and storing
information as a permanent memory.

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Tabulating Machine
 It was invented in 1890, by Herman
Hollerith, an American statistician. It
was a mechanical tabulator based
on punch cards. It could tabulate
statistics and record or sort data or
information. This machine was used
in the 1890 U.S. Census. Hollerith
also started the Holleriths Tabulating
Machine Company which later
became International Business
Machine (IBM) in 1924.

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Differential Analyzer
 It was the first electronic computer
introduced in the United States in
1930. It was an analog device
invented by Vannevar Bush. This
machine has vacuum tubes to switch
electrical signals to perform
calculations. It could do 25
calculations in few minutes.

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Mark I
 The next major changes in the
history of computer began in 1937
when Howard Aiken planned to
develop a machine that could
perform calculations involving large
numbers. In 1944, Mark I computer
was built as a partnership between
IBM and Harvard. It was the first
programmable digital computer.

Generations of a Computer
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 The computer has evolved from a large-sized
simple calculating machine to a smaller but much
more powerful machine.
 The evolution of computer to the current state is
defined in terms of the generations of computer.
 Each generation of computer is designed based
on a new technological development, resulting in
better, cheaper and smaller computers that are
more powerful, faster and efficient than their
predecessors.

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 Currently, there are five generations of computer.
In the following subsections, we will discuss the
generations of computer in terms of the
technology used by them (hardware and
software), computing characteristics (speed, i.e.,
number of instructions executed per second),
physical appearance, and their applications.

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 The first computers used vacuum tubes(a sealed
glass tube containing a near-vacuum which
allows the free passage of electric current.) for
circuitry and magnetic drums for memory.
 They were often enormous and taking up entire
room.
 First generation computers relied on machine
language.
 They were very expensive to operate and in
addition to using a great deal of electricity,
generated a lot of heat, which was often the
cause of malfunctions(defect or breakdown).
 The UNIVAC and ENIAC computers are
examples of first-generation computing devices.
First Generation Computers
(1940-1956)

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Advantages :
 It was only electronic device
 First device to hold memory
Disadvantages :
 Too bulky i.e large in size
 Vacuum tubes burn frequently
 They were producing heat
 Maintenance problems
First Generation Computers
(1940-1956)

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• Transistors replaced vacuum tubes and
ushered in the second generation of
computers.
• Second-generation computers moved from
cryptic binary machine language to
symbolic.
• High-level programming languages were
also being developed at this time, such as
early versions of COBOL and FORTRAN.
• These were also the first computers that
stored their instructions in their memory.
Second Generation Computers
(1956-1963)

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Advantages :
 Size reduced considerably
 The very fast
 Very much reliable
Disadvantages :
 They over heated quickly
 Maintenance problems
Second Generation Computers
(1956-1963)

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 The development of the integrated
circuit was the hallmark of the third
generation of computers.
 Transistors were miniaturized and placed
on siliconchips, called semiconductors.
 Instead of punched cards and printouts,
users interacted with third generation
computers through keyboards
and monitors and interfaced with
an operating system.
 Allowed the device to run many
different applications at one time.
Third Generation Computers
(1964-1971)

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Advantages :
 ICs are very small in size
 Improved performance
 Production cost cheap
Disadvantages :
 ICs are sophisticated
Third Generation Computers
(1964-1971)

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 The microprocessor brought the fourth
generation of computers, as thousands of
integrated circuits were built onto a single
silicon chip.
 The Intel 4004 chip, developed in 1971,
located all the components of the
computer.
 From the central processing unit and
memory to input/output controls—on a
single chip.
 . Fourth generation computers also saw
the development of GUIs, the mouse and
handheld devices.
Fourth Generation Computers
(1971-present)

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Fourth Generation Computers
(1971-present)

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 Fifth generation computing devices, based
on artificial intelligence.
 Are still in development, though there are some
applications, such as voice recognition.
 The use of parallel processing and
superconductors is helping to make artificial
intelligence a reality.
 The goal of fifth-generation computing is to
develop devices that respond to natural
language input and are capable of learning and
self-organization.
Fifth Generation Computers
(present and beyond)

Definition of a computer
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 By definition, a computer is an electronic device that
inputs data, processes data(converting it into
information that is useful to people) outputs and stores
information.
 Computers are controlled by programmed instructions
that transform the data into meaningful information.
 Generally a Computer is a device that accepts input,
processes it, stores data, and produces output.

Information Processing Cycle
 Steps followed to process data
 Input
 Processing
 Output
 Storage
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Parts of a Computer System
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Input
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 Input: Information provided to the computer by a
person, the environment, or another computer.
Examples of Input
 words and symbols
 numbers
 pictures
 audio signals from a microphone
 signals from another computer
 temperature, speed, pressures, etc. from sensors

Processing
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 Processing - manipulation of data.
 Data are symbols that represent raw facts, objects, and
ideas about people, places, events, and things that are
of importance in an organization.
 A computer program or software is a series of
instructions that tell a computer how to carry out a
processing task.
 Examples of Processing
 Arithmetic calculations
 Sorting a list
 Modifying pictures
 Drawing graphs

Output
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 Output - the result produced by a computer after
processing the data.
 Output device –displays, prints, or transmits the results
after processing.
 Examples of Output
 images on a monitor
 printed documents
 sounds
 signals to device controllers

Memory and Storage
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 Memory - the area of a computer that temporarily
holds data that is being processed or waiting to be
processed, stored, or output.
 Storage - The area where data can be left on a
permanent basis while it is not needed for processing.
 Examples of Storage
 magnetic disks
 CD-ROM (Compact Disk Read-Only Memory)
 magnetic tapes
 Flash disk
 Memory card
 Floppy disk

Personal and Home Uses of
Computers
 Computers allow people with
disabilities to do normal
activities.
 Shopping online
 Playing games with other
people
 Work from home
 Entertainment such as
listening to music, watching
videos etc.
 Enable communication
through the use of (electronic
mails) e-mails , chats etc.
Introduction to Computers 32

Business Uses of Computers
 Computers allow companies
to keep large amounts of
information at hand.
 Databases
 Makes ordering and
tracking resources quicker
and easier.
 Allows people to have
meetings from different
locations.
 Helps in information
management which eases
the process of decision
making .
 Computers allow people
across the world to

Educational Uses of Computers
 The Internet allows access
to hundreds of online
research materials.
 Allows colleagues to
correspond quickly about
ongoing research.
 Eases the process of
analysing research data.

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 Computer systems have four parts
 Hardware
 Software
 Data
 User (people)

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 Computer hardware:
 A computer's hardware consists of electronic devices;
the parts you can see and touch.
 In other words these are tangible parts of a computer.
 The term "device" refers to any piece of hardware
used by the computer, such as a keyboard, monitor,
modem, mouse, etc.
 These are mechanical devices that make up the
computer.

Computer Hardware Components
 Display Device
(Monitor or LCD
screen)
 System Unit
 Floppy disk drive
 CD ROM drive
 Hard disk drive
 Keyboard
 Mouse
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Other hardware components
 DVD drive (Digital Versatile Disk)
 CD writer (Compact disk)
 Sound card and speakers
 Modem (Modulate and Demodulate)
 Printers.
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Peripherals
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 A peripheral device designates equipment that might
be added to a computer system to enhance its
functionality.
 Examples:
 Printer
 Digital camera
 Scanner
 Joystick

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 Computer Software
 Is the set of instructions that makes the computer perform
tasks.
 The software is a part of the computer you cannot touch
but is very important.
 The software is all the programming that makes the
computer run; controlling everything that the computer
does.
 For any computer to function, it needs to have software
installed on it.

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 Data:
 Data consists of raw facts, which the computer can
manipulate and process into information that is useful to
people.
 Computerized data is digital, meaning that it has been
reduced to digits, or numbers. The computer stores and
reads all data as numbers.
 Users:
 People operating the computer.
 Tell the computer what to do.

Essential Computer Hardware
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 A computer’s hardware devices falls into one of the four
categories;
1. Processor
2. Memory
3. Input and Output
4. Storage

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 Processing Devices
 The procedure that transforms raw data into useful
information is called processing.
 The processor is like the brain of the computer.
 Organizes and carries out instructions from either the user
or software.
 Manipulate the data.
 Most computers have several processors.
 Central Processing Unit (CPU) refers to a computer’s
processor.

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 Memory devices
 Memory is made up of one or more sets of chips that
Store data or program instructions either temporarily or
permanently. Memory is divided into two types:
a) Random Access Memory (RAM)
 RAM holds data and program instructions temporarily while the
CPU works with them.
 RAM is volatile, meaning it holds data only when the power is on.
When the power is off, RAM's contents are lost.
 The “random” in RAM implies that any portion of RAM can be
accessed at anytime. This helps make RAM very fast.
 More RAM results in a faster system.

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b) Read Only Memory (ROM)
 Permanent storage of programs.
 ROM is called non-volatile memory because it never loses its
contents.
 Holds instructions that the computer needs to operate.
 Memory is measured in terms of:
 Kilobyte (KB) - 1,000 bytes
 Megabyte (MB) - 1,000,000 bytes
 Gigabyte (GB) - 1,000,000,000 bytes
 Terabyte (TB) - 1,000,000,000,000 bytes.

Position of RAM and ROM on the
Motherboard
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 Input and Output Devices
 Input devices accept data and instructions from the user
or from another computer system.
 Output devices return processed data to the user or to
another computer system.
 Input devices include: keyboard, mouse, scanner, digital
camera, microphone etc.
 Output devices include: monitor, printer, stereo speakers,
headphones etc.
 Communications devices (such as modems and
network interface cards) perform both input and output,
allowing computers to share information.

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 Storage Devices
 The purpose of storage is to hold data permanently,
even when the computer is turned off.
 Storage devices hold data not currently being used
by the CPU.
 Data is commonly stored on a magnetic or optical
disk.
 A disk drive is a device that reads data from and
writes data to a disk. Most new computers feature a
floppy disk drive, a hard disk drive, and an optical
disk drive.
 The most common optical storage devices are
CDROM and DVD-ROM drives.

Classification of Computers
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 The computer systems can be classified on the
following basis:
1. On the basis of size and portability
2. On the basis of data handling
3. On the basis of functionality and Usage
4. Based on Architecture
5. Based on Operating System
6. Based on Performance
7. Based on Usage Environment

Based on Size and Portability
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Classification According to Size
 There are four different sorts of computers based
on their size:
1. Supercomputers
2. Mainframe Computers
3. Minicomputers
4. Microcomputers.

Supercomputers
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 The most efficient computers in
terms of processing data and
performance are
supercomputers. These
computers are used for research
and exploratory purposes.
Supercomputers are exceedingly
large and highly expensive. It can
only fit in large, air-conditioned
spaces.
 Supercomputers are used for a
range of tasks, such as space
exploration, seismic research,
and the testing of nuclear

Supercomputers
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Features
 They make use of AI (Artificial intelligence)
 They are the fastest and strongest;
 They are very costly.
 They are enormous in size.
 They are employed by companies that manufacture goods.
 They process information at a rapid rate.
Applications Examples of
Supercomputers:
• Scientific research
• Defense and weapon
analysis
• Nuclear energy research
• Weather forecasting
• Petroleum research.
• CRAY T3D
• NEC-500.
• CDC 6600
• ABC (Atanasoff-
BerryComputer)
• ENIAC

Mainframe Computers
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Features
 Despite being less efficient than
supercomputers, mainframe
computers are nevertheless
extremely expensive. Large
corporations and governmental
organizations frequently employ
mainframe computers to run
everyday operations. They have the
ability to store and analyze a lot of
data. To maintain information on their
customers, students, and insurance
policyholders, banks, colleges, and
insurance companies utilize them.
They may also act as a server in a
network environment. Hundreds of
users may be managed
simultaneously by them.

Mainframe Computers
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Features
 They have enormous amounts of memory.
 They are capable of running several different operating
systems.
 They have a significant number of CPUs with powerful
processing speeds.
 Tightly Coupled Clustering Technology is employed.
Supercomputers:
• Banks & Hospitals for
preparing bills, Payrolls,
etc.
• In communication networks
such as the Internet where
they act as Servers.
• By Airline reservation
systems where information
of all the flights is stored.
• IBM 360,4381.
• ICL 39 Series.
• CDC Cyber series.
• BINAC
• UNIVAC

Minicomputers
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 Minicomputers are used by
small businesses and
industries. They go by the
term "Midrange Computers."
These minicomputers
frequently have several
users, just as mainframe
computers. They are a bit
slower than mainframe
computers.
 For example, the
manufacturing department
may employ minicomputers
to keep an eye on specific

Minicomputers
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Features:
 It is smaller than mainframes or supercomputers in
terms of size.
 In comparison to a mainframe or supercomputer, it is
less costly.
 It is able to perform many jobs at once.
 It may be utilized by several users simultaneously.
 It is utilized by small businesses.
Applications
• Used in scientific
laboratories
• Used in research
institutions
• Engineering plants
• Automatic processing
Also they are well adapted for
functions such as
• Accounting
• Word processing
• Database administration

Microcomputers
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 A microcomputer, sometimes
referred to as a personal
computer (PC), is a type of
computer that runs on a
smaller scale than traditional
computers (Personal
Computer). A component that
is commonly referred to as a
motherboard houses the
central processing unit (CPU),
a microprocessor, memory in
the form of ROM (Read Only
Memory), RAM (Random
Access Memory), I/O ports,
and a bus system of
connecting wires. They are the

Microcomputers
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Features:
 They are extensively employed for personal usage.
 They are smaller and comparably less expensive.
 Multi-user functionality is not supported.
 It has a limited computational capacity.
 They are quite simple to use.
Supercomputers:
• Microcomputers are
commonly used in:
• Training and learning
institutions such as
schools.
• Small business
enterprises, and
• Communication centers as
terminals.
• Desktop computer; is
designed to be placed on
top of an office desk
• Notebook or
laptop; portable
convenient for mobile
users.
• Personal Digital
Assistant(PDA); Is small
enough to fit in the pocket

Based on data handling
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Classification According to data handling
 According to data handling, there are three
different kinds of computers. They are as follows:
1. Analog Computers
2. Digital Computers
3. Hybrid Computers

Analogous Computers
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 Analog computers process analog data.
Temperature, pressure, weight, depth, and
voltage are a few examples of this type of data.
These have an infinite range of values and are
continuous quantities. The first computers were
analog, and they laid the groundwork for today's
digital computers.

Digital Computers
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 In digital computers, letters, numbers, and other
special symbols are represented by digits. On-off
(ON-OFF) inputs are used by digital computers,
and ON-OFF signals are also generated by them.
 An ON is often represented by a 1 and an OFF by
a 0, respectively. A digital computer is capable of
processing both numerical and non-numerical
data. In addition to doing fundamental arithmetic
operations like addition, subtraction,
multiplication, and division, it can also perform
logical operations.

Hybrid Computers
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 Computers that combine digital and analog
components are called hybrid computers. It
combines the best features of both types, having
the speed of an analog computer with the
memory and precision of a digital computer.
Hybrid computers are typically used in specific
applications where both forms of data need to be
processed. As an example, a gas pump contains
a processor that converts measurements of fuel
flow into information about quality and cost.

Based on functionality
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Classification According to functionality
 According to functionality, there are four
different kinds of computers. They are as follows:
1. Servers
2. Workstation
3. Information Appliances
4. Embedded Computers

Servers
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 Servers are nothing but dedicated computers
which are set-up to offer some services to the
clients.
 They are named depending on the type of service
they offered.
 Eg: security server, database server.

Workstation
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 Those are the computers designed to primarily to
be used by single user at a time.
 They run multi-user operating systems.
 They are the ones which we use for our day to
day personal / commercial work.

Information Appliances
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 They are the portable devices which are designed
to perform a limited set of tasks like basic
calculations, playing multimedia, browsing
internet etc.
 They are generally referred as the mobile
devices.
 They have very limited memory and flexibility and
generally run on “as-is” basis.

Personal Computers (PCs)
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 Used for general-purpose tasks such as word
processing, browsing, and entertainment.

Based on Architecture
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 Von Neumann Architecture: Computers that
use a single memory space for both data and
instructions. Most modern computers follow this
architecture.
 Harvard Architecture: Computers that have
separate memory spaces for data and
instructions, which can improve performance in
certain applications.

Based on Operating System
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 Windows PCs: Computers running the Microsoft
Windows operating system.
 macOS Computers: Computers manufactured
by Apple and running the macOS operating
system.
 Linux Computers: Computers running various
distributions of the Linux operating system.
 Unix Systems: Computers using Unix-like
operating systems, commonly found in servers
and workstations.

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 General-Purpose Computers:
 They are the most common types of computers in
use today. Their flexibility enables them to be
applied in a wide range of applications like;
 Document processing
 Performing calculations,
 Accounting,
 Data and information management
 Examples of general-purpose computers:
Mainframes, Minicomputers, Microcomputers &
Laptops used in most offices & schools.

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Special-purpose computer
 A special-purpose computer is designed to handle/accomplish a
particular specific task only. Such computers cannot perform any other
task except the one they were meant to do. Therefore, the programs
which are used in a special-purpose computer are fixed (hard-wired) at
the time of manufacture.
For example;
 In a computer Network, the Front End Processor (FEP) is only used to
control the communication of information between the various
workstations and the host computer.
 A Special-purpose computer is dedicated to a single task; hence it can
perform it quickly & very efficiently.
Examples of special-purpose computers:
 Robots used in a manufacturing industry for production only.
 Mobile phones used for communication only.
 Calculators that carry out calculations only.
 Computers used in Digital watches.
 Computers used in Petrol pumps.

Based on Usage Environment
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 Home Computers: PCs and laptops used for
personal tasks and entertainment.
 Office Computers: Used in workplaces for tasks
like document processing, communication, and
data management.
 Industrial Computers: Embedded computers
used in industrial automation and control
systems.
 Scientific Computers: Supercomputers and
high-performance computers used for scientific
research and simulations.

Computer Software
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 Software is a set of instructions that drive a computer
to perform specific tasks.
 These instructions tell the machine’s physical
components what to do.
 A set of instructions is often called a program.
 When a computer is using a particular program, it is
said to be running or executing the program.
 The two most common types of programs are system
software and application software.

Computer Software
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1) System software: Is any program that controls
the computer’s hardware or that can be used to
maintain the computer in some way so that it runs
more efficiently.
 System Software provides a platform for running
application software.
 There are three basic types of system software:
a) An operating system tells the computer how to
use its own components. All computers require
an operating system.
 The OS tells the computer how to interact with
the user and its own devices.
 Examples of operating systems include
Windows, Macintosh operating system and

Computer Software
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b) A network operating system allows computers to
communicate and share data across a network
while controlling network operations and
overseeing the network’s security. Example is
Windows server 2003.
c) A utility is a program that makes the computer
system easier to use or performs highly specialized
functions.
 Utilities are used to manage disks, troubleshoot
hardware problems, and perform other tasks
that the operating system itself may not be able
to do. For example a Symantec antivirus,
Partition Magic etc.

Computer Software
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2) Application Software: Tells the computer how to
accomplish specific tasks, such as word processing or
drawing, for the user.
 Some of the major categories of these applications
include:
 Word processing software for creating text-based
documents
 Spreadsheets for creating numeric-based documents
such as budgets.
 Presentation programs for creating and presenting
electronic slide shows.
 Graphics programs for designing illustrations or
manipulating photographs, movies etc.
 Database management software for building and

Data and Information
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 Data are the words, numbers, symbols and graphics
that describe people, events, things, and ideas.
 Data becomes information when it is used as the
basis for initiating some action or for making a
decision.
 Information are the words, numbers, and graphics
used as the basis for human actions and decisions.
 A set of data that has been given a name is called a
file.
 A file that a user can open and use is called
document.
 A folder is a place where groups of computer files
and other folders can be kept and organized.

Files
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 A file is a named collection of data, stored on a
storage medium such as a hard disk.
 There are two types of files
 Data files contains text, images, or other data that can
be used by a program.
 Executable files contains programs or instructions that
tell the computer how to perform a task.
 Filename extensions describe a file’s contents. For
example Executable files usually end in .exe, word
files end in .doc, adobe acrobat documents end in .pdf
etc.

Extensions and Formats
 A filename might be followed by a filename extension
that further describes the file contents.
 Word files end in .doc
 Excel files end in .xls
 The file format is the arrangement of data in a file and
the coding scheme that is used to represent the data.
 The native file format is the format that is saved by
the application that created it.
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Intro Computers in 40 Characters

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