2. Contents
• Introduction
• Evolution of computers
• Generations of computers
• Classification of computers
• The computer system
• Application of computer
3. Introduction
• In olden days people used fingers or pebbles to compute
• The term computer is derived from word compute, which
means to calculate.
• Computer is an electronic device which is used to
perform calculations and diverse operations with the help
of instructions to process data and achieve the desired
results.
• Covers huge area of applications such as education,
industries, government, medicine, research areas, music
and arts etc.
• Millions of complex calculations can be performed in a
fraction of second to achieve the desired result.
• Used in video conferencing, emails etc
4. Characteristics of computers
• Speed
– Computers process the data in an extremely fast rate at millions
(MHz) or billions instructions per second.
– Computer will finish the task in seconds when a human being
will take weeks together to finish the task.
• Accuracy
– Computers are always accurate
– It depends on the instructions and the type of machine used.
– Faulty instructions may lead to faulty results known as Garbage
in Garbage Out (GIGO)
5. • Diligence
– Computer never suffers from tiredness or lack of concentration.
– Any number of instruction it should perform, it will perform in the
same accuracy and speed as in the first calculations.
• Reliability
– Measurement of performance of a computer
– Computer performing without any failure
– Computers do not want any human interference in processing its
instructions
– It has its own built-in diagnostics capabilities which helps in
continuous monitoring of the system.
6. • Storage Capability
– They can store a large amount of data and recall the information
at any time instantaneously.
– Main memory is small, secondary memory is used for bulk
storage of data
– Data is bought from secondary storage to main memory
• Versatility
– Can perform many kinds of tasks with an equal ease
– Editing of letter, next movement you can have the system for
hearing music and in between you can print any document
• Resource sharing
– Computers connect to each other
– Sharing of costly resources like printers
– Data can be shared between systems in a network
7. • Some programs work fine for some time, later
after a period of time suddenly it produces an
error
• Happens due to rare combinations of events or
error in the instruction provided by the user.
• Computer requires a regular checking so that
works to give the correct results.
• Computers have to be installed in dust free
environments
8. Evolution of computers
• In the beginning the task was to simply counting
or adding people used either their fingers or
pebbles along lines in the sand.
• People in Asia Minor built a counting device
called abacus.
• Users calculate by sliding the beads arranged in
the rack
• Even now used for fast calculations by human
beings.
10. • Next significant advancement in computing
devices was Pascaline
• In 1642, A French mathematician , Blaise
Pascal invented the first functional automatic
calculator
• Eight movable dials to add numbers up to eight
figures long
• In 1694, German Mathematician Gottfried
Wilhem von Leibniz, extended Pascal’s design
to perform division and multiplication and to find
a square root known as Stepped Reckoner.
13. • In 1801, Joseph-Marie Jacquard, a Frenchman,
invented the Jacquard’s loom. Jacquard’s loom
used punch card to program pattern that were
outputted as woven fabrics by the loom.
15. • Real beginning of computers era started with
English mathematics professor named “Charles
Babbage”
• In 1822, he proposed a machine which could
perform differential equations called Difference
Engine.
• Powered by steam & as large as a locomotive,
the machine had the capacity to perform
calculations & print the results.
17. • Charles Babbage kept his research on, he
invented a machine called “Analytical Engine”.
• Had input devices in the form of perforated
cards containing operating instructions and
“store” for memory of 1000 numbers up to 50
decimal digits long.
• Had a controlling unit to allow instructions in any
sequence and output devices to print the results.
• He borrowed the idea of punch cards to encode
the machine instructions from Joseph-Marie
Jacquard’s Loom
19. • In 1889, Herman Hollerith , worked for US
Cencus Bureau used the concept of
Jacquard’s Loom for computing
• Hollerith used the cards to store the data,
which he fed into a machine that compiled
the results mechanically.
21. Mark I
• which was built in partnership between Harvard
Aiken and IBM in 1944
• This electronic machine used relays and
electromagnetic components to replace
mechanical components.
23. ENIAC
• 1946, John Eckert, John Mauchly of the Moore
School of Engineering at University if
Pennsylania developed Electronic Numerical
Integrator and Calculator (ENIAC)
• This machine used electronic vacuum tubes to
make internal parts of computer.
25. • Later on, Eckert and Mauchly also proposed the
development of the Electronic Discrete Variable
Automatic Computer (EDVAC)
• It had a capability of storing the program in it.
• It had a capablity of conditional transfer of control , I.e.
computer could stop any time and then resume
operations.
• 1949,Cambridge University, Maurice Wilkes developed
the Electronic Delay Storage Automatic
Calculator(EDSAC)
• This machine used mercury delay lines for memory and
vacuum tubes for logic
• 1951, Eckert, Mauchly Corporation manufactured
Universal Automatic Computer (UNIVAC)
26. • 1960, efforts to design and develop the fastest
possible computer with greatest capacity
reached a turning point with Livermore
Advanced Research Computer (LARC) which
had access time of less than 1 micro seconds
and total capacity of 10,000,000 words.
• During 1970’s the trend shifted towards larger
range of applications for cheaper computer
system.
• 1980s, Very Large Scale Integration (VLSI) ,
thousands of transistors placed on single chip.
27. • Then came personal computers, which are
programmable machines small enough and
inexpensive enough to be purchased and used
by individuals.
• 1980s, PCs run by microprocessor that were
capable of handling 32 bits of data at time and
4,000,000 instructions per second.
28. Generation of computers
• First generation (1940 to 1956)
– Vacuum tubes/ therminioc valve-based machines
– The first computers used vacuum tubes for circuitry
and magnetic drums for memory, and were often
enormous, taking up entire rooms.
– A magnetic drum is a metal cylinder with a magnetic
iron oxide material on which the data and programs
can be stored.
– Input was based on punched cards and paper tape
and outputs was in the form of printouts.
30. • These systems relied on the binary coded
language also called as machine language (0’s
and 1’s) to perform operations and were able to
solve only one problem at a time.
• Each machine would have a different binary
codes and hence were difficult to program.
• Ex: ENIAC,EDVAC,UNIVAC
31. Characteristics of first
generation computers
• Computers were based on vacuum tubes
• These were the fastest computing devices of
their times
• These computers were very large and required a
lot of space for installation
• 1000s of vacuum tubes will be used, hence
large amount of heat will be generated, therefore
air conditioning is necessary.
• Non-portable , very slow equipments
32. • Lacked versatility and speed
• Expensive , used large amount of electricity.
• Unreliable and very frequently prone to
hardware failures
• Machine language were used , hence difficult to
code
• Individual component had to be assembled
manually, hence commercial appeal of these
computers was poor.
33. Second Generation(1956-
1963):Transistors
• Transistors are superior to vacuum tubes.
• A transistor is made up to semi-conductor
material like germanium and silicon
• It has three leads and performs electrical
functions such as voltage, current or power
amplification with lower power requirements.
• Since transistors are small in size, the physical
size of the machine is reduced.
• Computers become smaller, faster, cheaper,
energy efficient and more reliable than their
predessors.
35. • Improvement was progress in language of the
machine language to assembly language.
• Assembly language uses a mnemonics
(abbrevations) eg: ADD, MULT
• Then came languages such as COBOL,
FORTON
• EX: PDP-8, IBM 1401 and IBM 7090
38. Characteristics of second generation
• Were based on transistor technology
• Were smaller compared to first generation
computers
• Computation time reduced to microseconds from
milliseconds, i.e. faster than first generation
• More reliable and less prone to hardware failure
• Were more portable and generated less amount
of heat.
• Assembly language was used, programming
became efficient and less cumbersome
• Still required air conditioning
• Manual assembly of individual components was
required
39. Third generation
• Integrated circuits IC began in this era.
• An IC consists of a single chip with many
components such as transistors and resistors
fabricated on it.
• This development reduced computers in size,
made it more reliable and efficient.
• Instead of punch cards , users interacted with
keyboard and mouse , interfaced with operating
system
• Ex: NCR 395 and B6500
42. Characteristics of third
generation
• Based on IC technology
• Able to reduce the computational time from
microseconds to nanoseconds
• Were easily portable, more reliable
• Consumes less power , generates less heat.
• Size of computers were small
• Maintenance cost is low
• Manual assembling of individual computer was
not required.
43. Fourth generation(1970s to till
date) Microprocessors
• Large Scale Integration LSI and VLSI
• LSI- thousands of transistors to be constructed
on small slice of silicon material
• VLSI- hundered of thousands of components on
to a single chip.
• ULSI- millions of components.
• More powerful, more reliable , compact and
affordable.
• PCs came into the market.
45. • Secondary memories became more economical,
smaller in physical and bigger capacity
• Computers could be linked to each other, lead to
INTERNET.
• Development of GUI , mouse and handheld
devices.
• Eg: Apple II, Altair 8800, CRAY-1
49. Charecterstics
• Microprocessor based
• Very small in size
• Cheapest among all other generation
• Portable and quite reliable
• Negligible heat is generated, no air conditioning
required.
• Production cost is very low
• Interconnection of devices, resource sharing
50. Fifth generation(present and
beyond): artificial intelligence
• Objectives were to create human like
computers which would give reasoning
and could decide by it self like “what-if-
then” analysis.
• Three charecterstics is:
• Mega chips
• Parallel processing
• Artificial Intelligence (AI)
51. • Mega chips:
– Super Large Scale Integration chips are used, results
in a microprocessor having millions of electronic
components on a single chip.
• Parallel Processing
– Use multiple processors and perform parallel
processing, accessing several instructions at a time
and working on them at same time.
• Artificial Intelligence (AI)
– Technologies that simulate and reproduce human
behavior, such as thinking, speaking, reasoning
52. Classification of computers
• We can divide into four major categories:
micro, mini , mainframes and
supercomputers
• Micro is further divided as,
– Desktop
– Handheld
– laptop
53.
54. 1. Microcomputers
– They are small, low cost digital computer , consists of
a microprocessor, a storage unit and an output
channel
– Peripherals like keyboard, monitor, printer, disk drives
etc makes up a microcomputer
– It includes desktop, laptop and hand held models
such as PDAs-personal Digital Assistants
55. A. Desktop Computers
– Also known as PC
– Stand-alone use by an individual
– System unit, monitor, keyboard, internal hard disk.
– not very expensive
– Ex: Apple, IBM, Dell,HP
A. Laptop
– Portable computer that a user can carry around.
– Also called as notebook computers
– Lightweight in nature
– Can use them anywhere at anytime
– No need of external power supply
– Requires charging of battery
56. C. Hand-held computers
PDAs that can conveniently be stored in pocket
Small portable computers slightly bigger than
common calculators
PDA user generally uses a pen or electronic stylus
to interact with PDA instead of keyboard for input
Also known as palmtop
No disk drive, use small cards to store the program
and data
Limited memory and less power when compared to
desktop computers
60. MiniComputers
• It is a small digital computer, which is normally
able to process and store less data than
mainframes but more than microcomputers.
• Size of about two – drawer filing cabinet
• Called as mid-range computers
• Designed to meet the computing needs of
several people simultaneously in a small to
medium sized business environment.
• Has capability of supporting from four to 200
users simultaneous
• Ex: PDP 11,IBM 8000 SERIES ,VAX 7500
61. Mainframes
• Is an ultra-high performance computer made for high
volume, processor intensive computing
• Has related peripherals that support large volumes of
data processing, high performance online transaction
processing , extensive data storage and retrieval.
• Second largest in capability and size , first is
supercomputers.
• Allows to store a large amount of data at centralized
location and to access and process these data from
different computers located at different location.
• Eg: IBM ES000, VAX 8000 , CDC 6600
62. Supercomputers
• Special purpose computers
• Used to maximize the number of floating point
operations per second (FLOPS)
• It has the highest processing speed at a given
time for solving scientific and engineering
problems
• Contains number of CPUs that operate in
parallel to make it faster.
• Speed ranges 400-10,000 MFLOPS
63. • Can deal with extensive amount of data and do
extensive calculations very quickly.
• The problems which took several years to
perform using paper and pencil and be solved in
few hours using supercomputers.
• Used as aerodynamics , metrology, plasma
physics, to simulate defence situations by
military for training
• Limited market and expensive
• Ex: CRAY-3, Cyber 205 , PARAM
64. The computer system
• A computer consists of interrelated components
that work together with the aim if converting data
into information.
• People perception is computer is an intelligent
thinking machine.
• Not true, because computer has to be instructed
exactly what to do and how to do.
• Instructions given is called programs.
65. Components of a computer
system
• CPU: performs processing of instructions and
data inside the computer
• Input unit: accepts instructions and data
• Output unit: communicates the results to the
user
• Storage unit: unit stores temporary and final
results.
66.
67.
68. Central processing unit
• Also known as processor, brain of the computer
system that process data and converts it into
information.
• CPU works with data in discrete form i.e. either 0
or 1.
• It counts, lists , compares and rearranges the
binary digit of data according to the program
instructions stored within memory.
• Eventually the results of these operations are
translated into characters, numbers and symbols
that can be understood by user.
69. • Three parts
• Arithmetic logic unit ALU
– It performs arithmatic operations like addition,
subtraction and logical operations like AND, OR on
the data available to it
– When operations has to be performed the data is
transferred from the memory to the ALU
– After performing the operation , the result is sent into
the memory.
– This transfer can happen many times till the operation
finishes completely.
70. • Control unit
– Checks correctness of the sequence of the operation
fetches the program instruction from the memory unit
– Interprets them and correct execution of the program.
– Controls I/O devices and directs functioning of other
units of computers.
• Registers
– High-speed temporary memory unit that can hold
varied information such as data , instructions,
addresses, intermediate results of the calculations.
– Esp. they hold data that CPU is currently working on.
– Considered as the CPU working memory, it helps in
speeding the computer.
71. Input and output unit
• A input unit accepts the instruction and data
from the user with the help of input devices such
as keyboard , mouse light pen
• Data entered from various input devices will be
in different form, input unit converts them into
the form that computer can understand.
• Later it supplies this converted data to computer
for further processing.
72. • An output unit performs opposite of input unit.
• Accepts the output produced by the computer ,
converts them into the form understandable by
the user and supplies it with the help of output
devices such as monitor, printer, plotter etc.
• Storage unit is to store the input entered through
input unit before processing starts and store the
results produced by the computer before
supplying them into output unit.
73. • Storage unit comprises two types: primary and
secondary storage
• Primary memory also called as main memory,
holds the instructions and data currently being
processed by the CPU, intermediate results and
recent processed data.
• Primary memory is quite expensive and has little
storage capacity.
• Eg: RAM
• Secondary storage is less expensive and has
high storage capacity
• Eg: hard disks, floppy disks, compact disks etc
75. • A computer performs three basic steps to
complete any task
– Input
– Processing
– Output
• A task is assigned to a computer in a set of step-
by-step instructions which is known as a
program.
76. • Step1-
– the computer accepts the input. The computer input
is whatever entered or fed into a computer system
– Eg: words and symbols in document, number for a
calculation, instructions for a completing process.
• Step2-
– the computer process the data
– The computer follows the instruction using the data
that have been input.
77. • Step 3:
– The computer produces output.
– Computer output is the information that has been
produced by a computer
– Eg: reports, documents and graphs.
79. Applications of computer
• Helps in efficient operation, saves time but also
saves paper work.
• Science:
– scientists use to develop theories, to analyze and to
test, the data
– Fast speed and the accuracy of the computer allows
scientific analyses to be carried out.
– To study the pattern of weather, effects of
earthquakes
– Information about solar system with the help of
sateliites.
80. • Education
– Classrooms , libraries , museums etc to make
education more interesting
– To do computer based study
– Video conferencing
• Medicine and Healthcare
– Doctors use computers for right diagnosing of the
patient.
– CAT, MRI scans are used for getting reports of the
internal organs of person’s body.
• Engineering/Architecture/Manufacturing
– For designing and drawing
– Can create three dimensional figures like reality.
– Computer-Aided Manufacturing (CAM) is used in
designing the product
81. • Entertainment
– Controls image and sounds
– Special effects, mesmerize the audience
– computerized animation, colorful graphics
• Communication
– E-mail, it saves time, avoids wastage of paper
– Receiver can read whenever he is free and save it ,
reply it, forward it or delete it from the computer
• Business application
– Real time applications such as sales counter, where
immediate response is required
– On business many computers are connected on
internet , shares data and resources
82. • Publishing
– Software named Desktop Publishing (DTP), with the
help of computer and laser printer, one can perform
the publishing job by oneself.
• Banking
– ATM(Automated teller machine)
– Inter-branch transaction, making drafts, drawing
cheques etc can be performed without any delay.
