lecture 2

INTRODUCTION TOCOMPUTER SCIENCE
CSC 1302
LECTURE 2
Department of Maths and Computer-
Science
Faculty of Natural and Applied Science
BY
UMAR DANJUMA MAIWADA

HARDWARE
 It is the physical component of the computer which we
can see and touch.
 Hardware is made up of devices or units.
 These include: input devices
 Processing devices
 Output devices
 Storage devices
2

RELATIONSHIP BETWEEN HARDWARE AND
SOFTWARE
 Both of them must work together to make a
computer produce a useful output.
 Software cannot be utilized without
supporting hardware.
 Software development is very expensive
and is a continuing expense.
 A software acts as an interface between the
user and the hardware.
3

SOFTWARE
 It is the collection of programs in the computer
 Which we can see at times but cannot touch
 A program is a sequence of instructions written to
solve a particular problem.
 There are two types of software; System Software
and Application Software.
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SYSTEM SOFTWARE
 These are programs that control the
operation of any computer.
 Example booting, loading, execution.
 System software include OS, language
translators
 System software are generally prepared by
computer manufactures.
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APPLICATION SOFTWARE
 They are designed to perform specific task for us.
 All software applications prepared in the computer lab
can come under the category of Application software.
 Types of application software include:
 Word processing e.g Ms word, word star, word perfect
 Spreadsheet e.g Ms excel, LOTUS
 Computer graphics e.g photopaint, corel draw, photoshop
 Database e.g Ms access,
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UTILITY SOFTWARE
 Example Norton, McAfee
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PERIPHERALS
 They are those external devices that must be
attached to the system unit for them to work.
 Example: mouse
 Lightpen
 Printer
 Modem
 Ups
 Scanner
 Projector
8

CHARACTERISTICS OF A COMPUTER
 Speed: Computer carries out every assignment and
processing very fast. It works faster than calculators,
four figure table, etc. it’s internal speed is almost
instantaneous.
 Storage: A computer would store information or data
once you instruct it to do so. It stores them inside its
storage devices.
 Accuracy: Every instruction is reliably carried out.
Computers can perform operations and process data
faster but with accurate results and no errors.
 Versatility: Computer is a versatile machine. They are
used in various fields.
 Multitasking: Multitasking is also a computer
characteristic. Computers can perform several tasks at a
time.
 Communication: Computers have the ability to
communicate, but of course there needs some sort of
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CLASSIFICATION OF COMPUTERS
Computers can be classified according to
i) Mode of operation
ii) Size and speed
iii) Generation
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MODE OF OPERATION
 Computers can be divided into Analog, Digital and
Hybrid systems.
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ANALOG COMPUTERS
 Data is recognized as a continuous measurement
of a physical property like voltage, speed, pressure.
 Readings on a dial or graphs are obtained as the
output.
 They do not directly interact with numbers
 They deal with variables measured along a
continues scale
 an analog computer must be able to accept inputs
which vary with respect to time and directly apply
these inputs to various devices within the computer
which performs the computing operations of
additions, subtraction, multiplication, division,
integration and function generation.
12

DIGITAL COMPUTERS
 These are high speed electronic devices.
 These devices are programmable.
 They operate on discrete data.
 They process data by way of mathematical
calculations, comparison, sorting.
 It works basically by directly counting numbers that
represent numerals.
 They represent information discretely and use a binary
(two-step) system that represents each piece of
information as a series of zeroes and ones.
 They are divided into two
 Specific purpose: which has been designed to perform one
specific task.
 General purpose: which can store different programs and is
also reprogrammable.
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HYBRID COMPUTERS
 They combine the speed of analog computers and
accuracy of digital computers.
 It is the one in which desirable characteristics of both
the Analog and Digital computers are integrated.
 It has the speed of analog computer and the memory
and accuracy of digital computer.
 An analog device is used to measures patient's blood
pressure and temperature etc, which are then converted
and displayed in the form of digits. Hybrid computers for
example are used for scientific calculations, in defence
and radar systems.
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SIZE
15
Continuat
ion
 Supercomputer
 Mainframe Computer
 Minicomputer
 Microcomputer

SUPERCOMPUTER
 It is the most powerful
 It is the most expensive
 They are designed to perform scientific application
 Its speed is very important
 This is known as parallel processing.
 The speed of each address in the location holds 64bits
of information.
 The time required to execute a single operation may be
as low as 4 nanoseconds.
 It can be accommodated in large air-conditioned
rooms.
 Super computers have multiple processors which
process multiple instructions at the same time.
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Uses of Supercomputer
17
• Space exploration
• Earthquake studies
• Weather forecasting
• Nuclear weapons testing

Mainframe computer
 Main frame computers are very large computers which
process data at very high speeds of the order of
several million instructions per second.
 They have the flexibility to operate automatically from
2 to 8 bytes in the same unit of time.
 Several microprocessors are used in place of the
single microprocessor used in micro and mini.
 The result is that these systems can process data
much faster.
 Government organizations uses Mainframes to run
their business operations.
 Mainframes can also process and store large amount
of data. Banks, educational institutions and insurance
companies use mainframe computers to store data
about their customers, students & insurance policy
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MINICOMPUTER
 It is a small general purpose computers varying in
size from a desktop model to a unit the size of a
four drawer filing cabinet.
 They have higher memory capacity and more
storage capacity with higher speeds.
 They are mainly used in applications like payrolls,
financial accounting, Computer aided design.
 One of the most important uses of minis is in the
distributed data processing networks.
 A minicomputer is a multiprocessing system
capable of supporting from 4 to 200 users
simultaneously.
 Minicomputers are used by small businesses and
19

MICROCOMPUTER
 They are widely used in day to day applications like office
automation, and professional applications.
 They have Smallest memory and less power.
 It is the smallest general purpose computer system which
can execute programs to perform a variety of instructions.
 It has all the functional elements found in a larger systems.
 Desktop computers, laptops, personal digital assistant
(PDA), tablets and smartphones are all types of
microcomputers.
 These computers are the cheapest among the other three
types of computers.
 They are specially designed for general usage like
entertainment, education and work purposes.
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COMPUTER GENERATIONS
 The present day computer, however, has also
undergone rapid change during the last fifty years.
 This period, during which the evolution of computer
took place, can be divided into five distinct phases
known as Generations of Computers.
 Each phase is distinguished from others on the
basis of the type of switching circuits used.
21

FIRST GENERATION COMPUTERS
 1940-1956
 Vacuum Tubes
 First generation computers relied on machine
language, the lowest-level programming language
understood by computers, to perform operations,
and they could only solve one problem at a time,
and it could take days or weeks to set-up a new
problem.
 They were huge, slow, expensive, and often
unreliable.
 They gave off so much heat, even with huge
coolers
 Vacuum tubes still overheated regularly
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PUNCHED CARDS FOR DATA INPUT,
PUNCHED CARDS AND PAPER TAPE FOR OUTPUT,
MACHINE LANGUAGE FOR WRITING PROGRAMS,
MAGNETIC TAPES AND DRUMS FOR EXTERNAL
STORAGE.
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 Punch card  Vacuum tube
 Paper tape

SECOND GENERATION
 1956-1963
 Transistors
 The transistors was faster, more reliable, smaller and
much cheaper to build than the vacuum tube.
 They gave off no heat compared to vacuum tube.
 One transistor replaced the equivalent of 40 vacuum
tubes.
 Second-generation computers still relied on punched
cards for input and printouts for output.
 Second-generation computers moved from cryptic
binary machine language to symbolic, or assembly
languages, which allowed programmers to specify
instructions in words.
 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, which moved from a
24

SIZE OF THE COMPUTERS STARTED REDUCING,
ASSEMBLY LANGUAGE STARTED BEING USED IN
PLACE OF MACHINE LANGUAGE,
CONCEPT OF STORED PROGRAM EMERGED,
HIGH LEVEL LANGUAGES WERE INVENTED.
 Transistor
25

THIRD GENERATION
 1964-1971
 Integrated Circuits (ICs)
 They carry out instructions in billionths of a
second.
 Transistors were miniaturized and placed on silicon
chips, called semiconductors, which drastically
increased the speed and efficiency of computers.
 Instead of punched cards and printouts, users
interacted with third generation computers through
keyboards and monitors and interfaced with an
operating system, which allowed the device to run
many different applications at one time with a
central program that monitored the memory.
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PHENOMENAL INCREASE IN COMPUTATION SPEED,
SUBSTANTIAL REDUCTION IN SIZE AND POWER
CONSUMPTION OF THE MACHINES,
USE OF MAGNETIC TAPES AND DRUMS FOR
EXTERNAL STORAGE,
DESIGN-OF OPERATING SYSTEMS AND NEW
HIGHER LEVEL LANGUAGES,
COMMERCIAL PRODUCTION OF COMPUTERS.
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 Integrated circuit  Integrated circuit

FOURTH GENERATION
 1971- Present
 Microprocessors
 Very large scale Ics which is millions of transistors
put together onto one Ics chip.
 More calculation and faster speed could be reached
by computers.
 They are used for personal use.
 As these small computers became more powerful,
they could be linked together to form networks,
which eventually led to the development of the
Internet. 28

USE OF VERY LARGE SCALE INTEGRATION,
INVENTION OF MICROCOMPUTERS,
INTRODUCTION OF PERSONAL COMPUTERS,
NETWORKING,
FOURTH GENERATION LANGUAGES.
 Very large scale integrated circuit
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FIFTH GENERATION
 Present and Beyond
 Artificial Intelligence
 They are still in development, though there are some
applications, such as voice recognition, that are being
used today.
 The goal of fifth-generation computing is to develop
devices that respond to natural language input and are
capable of learning and self-organization.
 Computers would be able to accept spoken words as
input (voice recognition).
 Two such advances are parallel processing where
many CPUs work as one and advance in
superconductor technology which allows the flow of
electricity with little or no resistance, greatly improving
30

QUESTIONS???
THANK YOU FOR YOUR ATTENTION
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