Transcript File - Prof J. Noorul Ameen ME

UNIT-I
Introduction To Computers
Introduction to Computer
• Early days people use fingers for
computing purpose.
• As years go, the computing needs also
grew. This leads to the invention of
calculators and computers.
• The term computer is derived from the
word compute, it means to calculate.
Definition
• Computer is an electronic device. It
accepts data, process the data and gives
the desired output.
INPUT
COMPUTER
OUTPUT
Basic functions or operations
•
•
•
•
•
Input
Processing
Output
Storing
Controlling
Basic operations (Cont)
• Input
It is the process of getting the data from
the user or from somewhere else into the
computer to process.
• Processing
It is the process of converting the input
to output.
Basic operations (Cont)
• Output
It is the outcome or result of the
process.
• Storing
It is the process of saving the data. so
that it can be retrieved whenever needed.
Basic operations (Cont)
• Controlling
It is the process of directing the
sequence in which the operations to be
performed.
Applications of computer:
•
•
•
•
•
•
Business
Industry
Home
Education
Printing & publishing
Entertainment etc.,
CHARACTERISTICS OF
COMPUTER
CHARACTERISTICS OF COMPUTER
•
•
•
•
•
•
Speed
Accuracy
Diligence
Versatility
Reliability
Storage
CHARACTERISTICS OF COMPUTER (cont)
• Speed
The computer process the data
extremely fast. (i.e.) in millions (1,000,000)
of instructions and even more per second.
A computer can perform a huge task in
few sec where a human being may take
hours or even days to complete the same
task.
CHARACTERISTICS OF COMPUTER (cont)
• Accuracy
The degree of accuracy of computer is
very high and every calculation is
performed with the same accuracy. The
accuracy level is determined on the basis
of design of computer. The errors in
computer are due to human and
inaccurate data.
CHARACTERISTICS OF COMPUTER (cont)
• Diligence
A computer is free from tiredness, lack
of concentration etc. It can work for hours
without creating any error. If millions of
calculations are to be performed, a
computer will perform every calculation
with the same accuracy. Due to this
capability it overpowers human being in
routine type of work.
CHARACTERISTICS OF COMPUTER (cont)
• Versatility
It means the capacity to perform
completely different type of work. For
example At a moment a computer can be
used to draft a letter. Next moment it can
be used print a document or play a music
file etc.,
CHARACTERISTICS OF COMPUTER (cont)
• Reliability
It produces results without any error.
Only human made errors can occur
So they are trustworthy machines.
CHARACTERISTICS OF COMPUTER (cont)
• Storage
Computers are capable of storing huge
amount of data and it can be located and
retrieved very quickly. It uses storage
devices such as hard disk to store huge
amount of data.
Generations of Computers
Generations of Computers (Cont)
First Generation Computers(1940-1956):
• These computers were vacuum tube
based machines.
• They used magnetic drums for memory.
• Input were fed into the computer using
Punched cards
• The size of these computers were very
large and it produce more heat.
• They lacked in versatility and speed.
• They were more expensive.
First Generation Computers(1940-1956):
• Speed: Fastest computing device of its time
• Technology: Vacuum Tubes :
– Made up of glass contains filaments, when heated
generates electrons which helps in amplification and
de amplification of signals
• I/p & O/p : Punched card and print out
• Programming language: Machine level language
• Example:
– EDSAC: Electronic delay storage automatic calculator
– EDVAC: Electronic discrete variable automatic computer
First Generation Computers(1940-1956):
• Advantages:
– Fastest computing device of their time
– Execute complex mathematical problems in an efficient manner
• Disadvantages:
–
–
–
–
–
Large & Bulky
Difficult to program
Cannot be transferred from one place to another
These are special purpose computers
Generates huge amount of heat and hence prone to hardware
faults
Generations of Computers (Cont)
Second Generation Computers (19561963)
• Here the Transistor replaced the bulky
vacuum tubes.
• Transistors are smaller than vacuum tubes
and have higher operating speed.
• Thus the size of the computer got reduced
considerably.
• Manufacturing cost was also very low.
Second Generation Computers (1956-1963):
• Speed: Faster than first generation
• Technology: Transistor :
– Used to increase the power of incoming signals.
– It has 3 connections:
• Base : Through which incoming signals are sent
• Collector : Collects amplified signal
• Emitter : Emits amplified signal
• I/p & O/p : Punched card and print out
• Programming language: Assembly language
• Example:
– IBM 1401
– IBM 1620
Second Generation Computers (1956-1963):
• Advantages:
–
–
–
–
–
–
Fastest computing device of their time
Easy to program
Light weight
Low power consumption
Low maintenance
Transferred from one place to another easily
• Disadvantages:
– High cost
– Limited to special purpose tasks
– Generates considerable amount of heat
Generations of Computers (Cont)
Third Generation Computers (1964-1975)
• These computers were based on
Integrated Circuits (ICs) Technology.
• A single IC has many transistors, registers
and capacitors built on a single thin slice of
silicon.
• So that the size of the computer got further
reduced.
• These Computers were small in size, low
cost, large memory and processing speed
is very high.
Third Generation Computers (1964-1975):
• Speed: Fastest computing device of its time
• Technology: Integrated Circuits : Also known as micro
electronics technology
• Programming language: High level language
• Example:
– IBM 360
– Honeywell 6000
Third Generation Computers (1964-1975):
• Advantages:
–
–
–
–
–
–
–
Computational time was measured in nano seconds
Requires low power to operate
Small size
Installation is very easy
Able to execute any type of applications
More reliable & requires less maintenance
Easily transportable
• Disadvantages:
–
–
–
–
Storage capacity was very small
Performance will get degrade while executing large applications
Cost is very high
Required to be placed in air conditioned plates
Generations of Computers (Cont)
Fourth Generation Computers(1975-1989)
• It uses very large scale Integrated Circuits
(VLSI) built on a single silicon chip called
microprocessors .
• These computers are called microcomputers.
• Thus the size of the computer got reduced.
• The personal computer (PC) are comes
under the Fourth Generation.
Fourth Generation Computers (1975-1989):
• Speed: Fastest computing device of its time
• Technology: VLSI : Very large scale Integration
– It leads to the development of GUI, Operating
Systems, Various storage devices, I/O devices and
LAN
– It has 3 components:
• Microprocessors
• Memory
• I/O Controls
• Programming language: High level language
• Example:
– IBM PC series
– Apple Series
Fourth Generation Computers (1975-1989):
• Advantages:
–
–
–
–
Very powerful in terms of speed & time
Storage capacity is very high & it is very fast
Highly reliable and requires low maintenance
Provides user friendly environment using GUI(Graphical user
interface)
– Programs are highly portable
– Highly versatile and requires less power
• Disadvantages:
– The soldering of VLSI chips on the wiring board was not an easy
task
– Working of these computers depends on instructions given by
the programmer
Generations of Computers (Cont)
Fifth Generation Computer(1989-Till date)
• The speed is extremely high in fifth
generation computer.
• The concept of Artificial intelligence has been
introduced to allow the computer to take its
own decision.
• It is still in a developmental stage .
Fifth Generation Computers (1989-Till date):
• Speed: Faster of all times
• Technology: ULSI : Ultra large scale Integration
– It has more than10 million electronic components
– It increases the power & speed of the microprocessor
• Programming language:
– High level language
– Integrated development environment
• Example:
– Laptop
– PDA
Fifth Generation Computers (1989-Till date)
• Advantages:
–
–
–
–
–
Fastest & powerful computers till date
Able to execute a large no of application at very high speed.
ULSI Technology helps in decreasing the size of computers.
Multimedia features are available
Resource sharing is possible & is highly versatile
• Disadvantages:
– Lack of human like Intelligence
Classification of Computer
Classification of Computer
Computer
Based on
Applications
Based on
Operating Principles
1.
2.
3.
Analog
Computers
Digital
Computers
Hybrid
Computers
1.
2.
Special
Purpose
Computers
General
Purpose
Computers
Based on
Size & Capabilities
1.
2.
3.
4.
Micro
Computers
Mini
Computers
Mainframe
Computers
Super
Computers
Classification of Computer (Cont)
Microcomputer
• Microcomputer is at the lowest end of the
computer range in terms of speed and
storage capacity.
Eg: Desktop, Laptop, Tablet PC, Smart
Phones.
Classification of Computer (Cont)
Mini Computer
• This is designed to support more than one
user at a time. (up to 200 users)
• It possesses large storage capacity and
operates at a higher speed.
• This type of computer is generally used for
processing large volume of data in an
organisation.
• Eg:Servers in Local Area Networks (LAN).
Classification of Computer (Cont)
Mainframes
• They operate at very high speed, having
very large storage capacity and can
handle the work load of many users(more
than 200 users.
• They are generally used in centralised
databases.
Classification of Computer (Cont)
Supercomputer
• They are the fastest and most expensive
machines.
• They have high processing speed
compared to other computers.
• They have also multiprocessing technique.
• Supercomputers are mainly being used
for whether forecasting, biomedical
research, and other areas of science and
technology
BASIC ORGANISATION
OF
COMPUTER
Basic organisation of computer
I/P UNIT
MEMORY
UNIT
O/P UNIT
CACHE MEMORY
REGISTERS
ALU
CONTROL
UNIT
Block Diagram
of a Computer
System
Basic organisation of computer
• INPUT
– The input unit is used to feed information or
instruction to the computer.
– Input Devices:
• Keyboard
• Mouse
• Scanner…
Basic organisation of computer (cont)
• MEMORY UNIT
– Used to store
• Data
• Instructions
• Intermediate Results &
• Final Processed Results
– Types
• Primary
• Secondary
• Internal Processor memory
– Primary memory is used to store temporary data.
– Ex:RAM, ROM etc,.
– Secondary memory is used to store information permanently
– Ex:Hard disk.
– Internal Processor memory is used to store temporary
processor data
– Ex:CPU Registers
Basic organisation of computer (cont)
• CENTRAL PROCESSING UNIT (CPU)
– Responsible for processing the data & instruction and controlling
all other components
– Operation (4 Phases)
•
•
•
•
Fetching Instruction from the memory
Decoding the instruction
Executing the instructions
Storing the results in to the memory
– It contains the following components
• CONTROL UNIT
• ALU
• MEMORY
Basic organisation of computer (cont)
• CONTROL UNIT
– It controls all other units in the computer.
– It directs the sequence in which operations to
be performed.
– It also controls the flow of data between
various units.
Basic organisation of computer (cont)
• ARITHMETIC & LOGICAL UNIT
– It performs all arithmetic & logical operations.
– i.e. arithmetic operations like addition,
subtraction, multiplication, division etc,. And
logical operations like AND,OR,NOT etc,.
Basic organisation of computer (cont)
• Registers
– CPU contains a few special purpose, temporary storage
units called registers
– They are high speed memory locations
– Used for handling instructions, data & intermediate results
that are currently being processed
• Registers
1.
2.
3.
4.
Program Counter(PC)
Instruction Register(IR)
Memory Address Register(MAR)
Accumulator
Basic organisation of computer
• OUTPUT
– The output unit is used to display the result of
the process.
– Data processed by CPU is made available to
the end user by O/P devices
– Commonly used O/P devices:
• Monitor
• Printer
• Speaker
Components of Computers
Components of Computers
• Hardware
The physical components present in
the computer.
• Software
It is a collection of programs and it can
perform some operaions.
Components Present inside the
cabinet
•
•
•
•
•
Motherboard
Processor
SMPS
Disk drives
RAM & ROM etc,.
Types of Memory
MEMORY
PRIMARY
SECONDARY
SEQ.ACESS
RANDOM ACCESS
• Primary Memory:
It is used to store data temporary.
RAM
• Random Access Memory
• It is possible to randomly select and use
any location of the memory.
• It is a volatile memories i.e. It loose their
content when the power is switched off
ROM
• Read Only Memory
• The data in the ROM is permanent .
• It is a non-volatile memories i.e. It does
not loose their content when the power is
switched off .
PROM
• Programmable Read Only Memory
• It is supplied in blank by the manufacturer.
• It is possible to store program in PROM
chip.
• Once the programmes are written it cannot
be changed and remain even if power is
switched off.
EPROM
• Erasable Programmable Read Only
Memory.
• Information stored in EPROM can be
erased by exposing the chip in ultraviolet
light and it is reprogrammed using a
special programming facility.
EEPROM
• Electrically Erasable Programmable Read
Only Memory.
• Information stored in EEPROM can be
erased by applying some voltage.
• Secondary Memory:
It is used to store data permanently
• TYPES: sequential access , random
access
Sequential Access
Magnetic Tape:
• Magnetic tapes are used by large
computers like mainframe computers
where large volume of data is stored for a
longer time.
• The cost of storing data in tapes is
inexpensive.
• Tapes consist of magnetic materials that
store data permanently.
Random Access
Hard Disk:
• It uses circular disk ,coated with magnetic
material called platters.
• It rotates with very high speed inside the
drive.
• Data is stored on both the surface of the
disk.
• Each disk consists of a number of invisible
concentric circles called tracks.
• The information stored in a disk can be read
many times without affecting the stored data.
Magnetic Hard Disk Mechanism
Random Access (cont)
Optical disk
• It uses a circular plastic disk coated with
aluminium or silver storing data.
• The data are stored in the circular tracks.
• Laser beam is used for storing and
retrieve data from the disk
INPUT OUTPUT DEVICES
• Input Devices
Input devices are necessary to convert
our information or data in to a form which
can be understood by the computer.
• Eg: Keyboard, Mouse, MICR,OMR,OCR.
Keyboard
• This is the standard input device.
• The layout of keyboard is just like the
traditional typewriter of the type QWERTY.
• It also contains some extra command
keys and function keys.
• The computer can recognise the electrical
signals corresponding to the correct key
combination and processing is done
accordingly
Mouse
• Mouse is an input device.
• When the mouse is moved across a flat
surface the screen pointer is also moved
in the direction of mouse movement.
• It is easier to move the cursor through a
mouse
Magnetic Ink Character
Recognition (MICR)
• This is widely used by banks to process
large volumes of cheques and drafts.
• Cheques are put inside the MICR.
• As they enter the reading unit ,the
magnetic field which causes the read head
to recognise the character of the cheques.
Optical Mark Reader (OMR):
• This technique is used in objective type
tests and the answer are marked by
darkening a square or circular space by
pencil or pen.
• These answer sheets are directly fed to a
computer for grading where OMR is used.
Output Devices
Visual Display Unit
• The most popular output device is the
Visual Display Unit (VDU).
• It is also called the monitor.
• Monitor is used to display the input data
and to receive massages from the
computer.
• It can be color or monochrome.
Printer
• It is an important output device which can
be used to get a printed copy of the
processed text or result on paper.
• printers are classified as impact and
non-impact printers.
NUMBER SYSTEM
Number System
• Number Base B => B symbols
–Base 16(Hexa):0, 1,……9, A ,…, E, F
–Base 10 (Decimal): 0, 1, 2,……, 7, 8, 9
–Base 8(Octal): 0, 1, 2, 3, 4, 5, 6, 7
–Base 2 (Binary): 0, 1
NUMBER SYSTEM
• Number System
– A computer is a digital system that stores and process data in
the form of 0’s and 1’s(Binary/Machine language)
– Hence there is a need to change the data in the form of 0’s &1’s
• Positional Number System
– Numbers are represented using some symbols called digits and
the values of these no’s can be determined by taking the position
of digits
– Catagories:
• Decimal System
• Binary System
• Hexa Decimal System
• Octal System
NUMBER SYSTEM ….
• Decimal System
– Uses 10 as a base & is called base 10 no system
– 10 symbols are available for representing values (0-9)
– Used to represent both integer & floating point values
• Representation
– 6543.12410
– (6x10^3)+(5x10^2)+(4x10^1)+(3x10^0)+(1x10^-1)+(2x10^2)+(4x10^-3)
= 6543.12410
NUMBER SYSTEM ….
• Binary System
– Uses 2 as a base & is called base 2 no system
– 2 symbols are available for representing values (0 & 1)
• Representation
– 101001.01012
– (1x2^5)+(0x2^4)+(1x2^3)+(0x2^2)+(0x2^1)+(1x2^0)+(0x2^1)+(1x2^-2)+(0x2^-3)+(1x2^-4)
= 41.312510
NUMBER SYSTEM ….
• Hexa Decimal System
– Uses 16 as a base & is called base 16 no system
– 16 symbols are available for representing values (0-9 & letters
A,B,C,D,E,F)
• Representation
– 4A9.2B16
– (4x16^2)+(10x16^1)+(9x16^0)+(2x16^-1)+(11x16^-2)
= 1193.167910
NUMBER SYSTEM ….
• Octal System
– Uses 8 as a base & is called base 8 no system
– 8 symbols are available for representing values (0-7)
• Representation
– 215.438
– (2x8^2)+(1x8^1)+(5x8^0)+(4x8^-1)+(3x8^-2)
= 141.546910
NUMBER SYSTEM ….
DECIMAL
BINARY
OCTAL
HEXA DECI..
0
0
0
0
1
1
1
1
2
10
2
2
3
11
3
3
4
100
4
4
5
101
5
5
6
110
6
6
7
111
7
7
8
1000
10
8
9
1001
11
9
10
1010
12
A
11
1011
13
B
12
1100
14
C
13
1101
15
D
14
1110
16
E
15
1111
17
F
16
10000
20
Decimal to Binary
Conversion of 2510 to Binary
2 25
2 12 -1
2 6-0
2 3-0
1-1
2510=110012
• Binary to decimal conversion
11001
1X20
0X21
0X22
1X23
1X24
=
=
=
=
=
1
0
0
8
16
2510
Decimal to Octal
Conversion of 12510 to Octal
8 125
8 15 - 5
1 -7
12510=1758
• Octal to decimal conversion
175
5X80
7X81
1X82
=
5
= 56
= 64
125
1758 = 12510
Conversion of 8410 to Octal
8 84
8 10 - 4
1 -2
8410=1248
• Octal to decimal conversion
124
4X80
2X81
1X82
1248 = 8410
=
=
=
4
16
64
84
Decimal to Hexa
Conversion of 45010 to Hexadecimal
16 450
16 28 - 2
1 - 12
45010=1C216
• Hexa to decimal conversion
1C2
2X160
12X161
1X162
1C216 = 45010
=
=
=
2
192
256
450
Conversion of 38510 to Hexadecimal
16 385
16 24 - 1
1 - 8
38510=18116
• Hexa to decimal conversion
181
1X160
8X161
1X162
18116 = 38510
=
=
=
1
128
256
385
Conversion of 25.12510 to Binary
2 25
2 12 -1
2 6-0
2 3-0
1-1
2510=110012
0.125 X 2 = 0.250
0.250 X 2 = 0.5
0.5 X 2 = 1.0
25.12510 = 11001.0012
• Binary to decimal conversion
11001.001
1X2-3 =
0X2-2 =
0X2-1 =
1X20 =
0X21 =
0X22 =
1X23 =
1X24 =
0.125
0
0
1
0
0
8
16
25.12510
Conversion of 84.25010 to Octal
8 84
8 10 - 4
1 -2
8410=1248
0.250 X 8 = 2.000
25.12310 = 124.28
• Octal to decimal conversion
124.2
2X8-1 =
4X80 =
2X81 =
1X82 =
0.25
1
0
0
25.25010
ASSIGNMENT
DECIMAL TO BINARY
•
•
•
•
•
43
79
107
241
476
DECIMAL TO OCTAL
•
•
•
•
•
39
152
284
758
2534
DECIMAL TO HEXA
•
•
•
•
•
75
826
3128
7359
4756
DECIMAL TO OTHER
• 63 BASE4
• 279 BASE6
• 161 BASE7
BINARY  OCTAL,HEXA
•
•
•
•
•
1010101
11010101011
111010110111
1011110111
101000101
OCTAL  HEXA
•
•
•
•
•
473
1235
724
5774
4625
• 75.12510 BASE2
• 356.52310 OCTAL
• 527.4210 HEXA