computer hardware system

1. Computer Hardware
SyStem
Course: B.Sc-CS
Subject: Fundamental Of Information Technology
Unit: I

2. History of Computers
• Charles Babbage - father of computer
– 1800’s planned analytical engine
• ENIAC - developed at end of WW II
• 1951 - 1963 1st and 2nd generation
– very large, used unreliable vacuum tubes
• 1963 - present - 3rd and 4th generation
– smaller, faster - use transistors and integrated circuits
2

3. History - Microcomputers
• Apple
– First sold in late 1970’s
– Developed by Jobs and Wozniak
• IBM Personal Computers
– First sold in 1981
– Was quickly accepted by businesses
– IBM compatibles soon developed
3

4. What Is a Computer?
• A computer is an electronic device that accepts data and
instructions from a user, manipulates the data according to the
instructions, displays the information in some way, and stores the
information for retrieval later
4

5. What is a computer?
• An electronic device that accepts input, processes the data and
instructions, produces output from the processing that is useful
and meaningful and stores the results for future use.
5

6. How Does A Computer Know What To
Do?
• It must be given a detailed set of instructions that tell it exactly
what to do.
• These instructions are called a computer program, or software.
6

7. Generation of ComputerGeneration of Computer
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8. Index
 1st
Generation Of Computer
 2nd
Generation Of Computer
 3rd
Generation Of Computer
 4th
Generation Of Computer
 5th
Generation Of Computer
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9. Introduction
The term Computer Generation is after use in relation to the
hard were of computer. Each phase of computer development
is known as separate generation of computer. Each phase of
development is characterized by type of switching circuits it
utilizes.
Most computer today use the idea of stored program.
Computer that was proposed by Dr.John Von Neumann in
1945.The Von Neumann architecture is based in three key
concept that are:
1)Data & instruction (program) are stored in a single read write
memory.
2)The memory content are addressable by location.
3)Excution takes place in sequential fashion.
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10. First Generation
[1949-55]
• The first generation of computer used the vaccume tube &
machine language was used for giving instruction. The first
generation computer used the concept ‘stored program'. The
computer of this generation were very large in size & their
programming was a difficult task.
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11. Some computer of this generation
are given below:
• ENIAC :-It has very small memory & it was used for
calculating trajectories of missiles.
• EDVAC:-The “Von Newmann” concept of stored program,
was also applied in EDVAC.
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12. Some key feature of first
generation:
• Used vacuumed tubes.
• Big computers.
• Electrically consumption high.
• Large Ac’s were necessary because the computer
generated heat.
12

13. The Second Generation
1956-65
• The second generation computer began with the advent
transistorized circuitry, invention of magnetic core &
development of magnetic disk storage devicer.These new
development made these computer more reliable. These
Industries in the application’s like Marketing, Production
planning etc.
13

14. Some key feature of second
generation:
• Transistor replaced vaccume tubes.
• Small in size.
• Less amount of heat was generated.
• Core memory was developed.
• First operating system was developed.
• Programming was in machine language as well as assembly
language.
14

15. The Third Generation
[1966-1975]
The third generation of computer replaced transister with
‘Integrated circuits’ popularly known as chips. The IC was
inverted by Jack kilby at Texas Instrument in 1958.The third
generation computer using integrated circuit Proved to be
highly reliable,relatively expensive & faster.
15

16. Some key feature of third
generation:
• Integrated circuits developed.
• Power consumption was low.
• Computer were smaller, faster & more reliable.
• High level languages (HLL) appeared.
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17. The Forth Generation
[1976-Present]
• The advent of the microprocessor chip marked
the beginning of the fourth generation
computer. Very Large Scale Integrated (VLSI)
circuits packing about 50,000 transistor in a
chip. The Hard disks are also available of the
size up to 80 GB.For larger disks RAID
technology give to storage hundreds of GB.
The CD ROM also becoming popular day by
day. The CD ROM of today can store up to
650 MBS information.
17

18. Some key features of forth
generation:
• Integrated circuits smaller & faster.
• Portable computer developed.
• Great development in data communication.
• Different types of secondary memory with high storage
capacity & fast access developed.
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19. The Fifth Generation
[Coming Generation]
Fifth Generation computing devices based on artificial
intelligence, are still in development. The goal of fifth
generation computing is to develop devices that response to
natural language input & are capable of learning & self
organization.
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20. Some key features of fifth
generation:
• Parallel Processing was done.
• Super conductors were used.
• Many processors are grouped to function as one large group
processor.
• A super conductor is a conductor through which electricity
can travel without any resistance resulting in faster transfer of
information between the components of computer.
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21. The CPU
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22. The CPU
• Converts data into information
• Control center
• Set of electronic circuitry that executes stored
program instructions
• Two parts
– Control Unit (CU)
– Arithmetic Logic Unit (ALU)
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23. Control Unit
CU
• Part of the hardware that is in-charge
• Directs the computer system to execute stored program
instructions
• Communicates with other parts of the hardware
23

24. Arithmetic / Logic Unit
ALU
Performs arithmetic operations
Performs logical operations
24

25. Arithmetic Operations
Addition
Subtraction
Multiplication
Division
25

26. Logical Operations
• Evaluates conditions
• Makes comparisons
• Can compare
– Numbers
– Letters
– Special characters
26

27. Basic Logic Gates
• A gate is a device that performs a basic operation on
electrical signals
• Gates are combined into circuits to perform more
complicated tasks
1.27

28. Computers and Electricity
• There are three different, but equally powerful,
notational methods
for describing the behavior of gates
and circuits
– Boolean expressions
– logic diagrams
– truth tables
4–28

29. Computers and Electricity
• Boolean algebra: expressions in this algebraic
notation are an elegant and powerful way to
demonstrate the activity of electrical circuits
4–29

30. Computers and Electricity
• Logic diagram: a graphical representation of a
circuit
– Each type of gate is represented by a specific
graphical symbol
• Truth table: defines the function of a gate by listing
all possible input combinations that the gate could
encounter, and the corresponding output
4–30

31. Gates
• Let’s examine the processing of the following
four types of gates
– NOT
– AND
– OR
– XOR
• Typically, logic diagrams are black and white, and the
gates are distinguished only by their shape
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32. NOT Gate
• A NOT gate accepts one input value
and produces one output value
Figure Various representations of a NOT gate
32

33. NOT Gate
• By definition, if the input value for a NOT gate is 0,
the output value is 1, and if the input value is 1, the
output is 0
• A NOT gate is sometimes referred to as an inverter
because it inverts the input value
4–33

34. AND Gate
• An AND gate accepts two input signals
• If the two input values for an AND gate are both 1, the output
is 1; otherwise, the output is 0
Figure Various representations of an AND gate 34

35. OR Gate
• If the two input values are both 0, the output
value is 0; otherwise, the output is 1
Figure Various representations of a OR gate
35

36. XOR Gate
• XOR, or exclusive OR, gate
– An XOR gate produces 0 if its two inputs are the same, and
a 1 otherwise
– Note the difference between the XOR gate
and the OR gate; they differ only in one
input situation
– When both input signals are 1, the OR gate produces a 1 and
the XOR produces a 0
36

37. XOR Gate
Figure Various representations of an XOR gate
37

38. Presentation On
Computer Memory
38

39. What is Memory ?
As the word implies “memory” means the place
where we have to store any thing, this is very
essential part of human being just like this memory is
also very important for computer system because in
computer system we have to store some data or
information and for storing these items we need some
memory or space.
So that’s why we can say that memory is very
important part of computer system.
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40. About Memory
There are various units which are used to measure
computer memory
• Bit - Smallest unit of computer memory
• Byte - 8 bit = 1 byte
• Kilobyte - 1024 byte = 1 kb
• Megabyte - 1024 kb = 1 mb
• Gigabyte - 1024 mb = 1 gb
• Terabyte - 1024 gb = 1 tb
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41. Memory are classified into two types :-
1. Primary Memory :-
Primary memory also known as “main memory” or
“internal memory” which is located in the mother
board of system or as we say which is directly
connected to the CPU. It is the place where only
little bit of data are stored either by manufacturer or
by user.
This is further divided into two parts :-
 RAM
 ROM
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42. RAM
RAM also known as “random access memory” it stores
the data which the user currently uses or as we say it
stores the data temporary in it. RAM needs power or
electricity to work when the computer power is turned off
then all the data in it will be erased automatically.
This is a circuit which have its separate space or slot in
motherboard. This allows the computer to run the
software faster.
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43. ROM
Known as “Read Only Memory” as the word refers
mainly it can only read the data which in stored in it.
This memory is mainly used by our computer when
we just turn on our computer. It contains BIOS of
system. This is non-volatile in nature.
Mainly there are three types of ROM :-
PROM
EPROM
EEPROM
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44. PROM
Known as “programmable Read Only memory”. In
this when the data is stored then we have no right to
change or alter any data to it. In this the data is
written by Manufacturer company, even you can also
purchase blank PROM chip but it can be programmed
by special tool such as PROM programmers. In
general PC’s mainly PROM is used because we don’t
have to alter any data to it
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45. EPROM
Known as “Erasable PROM” as the word refers
“erasable” means we can change or erase the data. So
in EPROM we have right to change the data. In this
we can change the data with the help of ultra violet
rays. EPROM is much expensive than PROM.
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46. EEPROM
Known as “Electrically Erasable PROM” the type of
ROM which can be erased by electrical charges.
EEPROM can be erased one byte at anytime rather
than erasing the entire chip by ultra violet rays.
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47. Secondary Memory
The place where we store our personal data in computer system is
known as SM. In this we store data so that when the data is needed
we can easily retrieve it. This is the fundamental component of
comp. system. It is non volatile in nature so that we can not loose
the data when power supply is off.
There are two methods for accessing the data from it :-
1. Sequential – This is the method in which we search the data
sequentially or line by line until you find the desired data. E.g..
Magnetic tape, etc.
2. Direct – This is the method in which computer can go directly to
the information that the user wants.
e.g. magnetic disk, optical disk, etc.
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48. Now I am going to discuss some of the secondary storage
devices :-
1.Magnetic Tape :- Magnetic tape appears similar to the tape
used in music cassettes. It is a plastic tape with magnetic
coating. Mainly it is used to store music, movie, etc. it is not
used to store data in it because as we know it comes under
sequential access and it reads data line by line so that we can’t
find the exact location of data.
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49. 2. Magnetic Disk :- This is widely used popular
storage medium for direct access secondary storage.
This is the place where data are automatically save
when we click on save button. It is non- volatile so
that once data is stored in it will not lost when
power goes off. This is the storage device where we
mainly store or install OS for system.
Some of the magnetic disk are as follows :-
Hard Disk
Floppy Disk, etc.
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50. Hard Disk
Hard Disk also known as “Hard Drive” or “Fixed
Drive”. This is the place where we store our data or
information so that we can retrieve for further use.
This is the place where we install our OS so that we
can run our computer. Hard disk comes fix in our
system and if you require more hard disk then it
comes in removable also. The average computer
today comes with a 250 to 500 gb hard drive.
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51. Floppy Disk
This is removable, round, flat piece of Mylar plastic,
coated with a ferric oxide. this kind of disk is read
and written by Floppy Disk Drive (FDD), which is a
device which performs basic operations on disk
including reading and writing of data to it. This was
used to transfer data from one computer to another.
Earlier 5 ¼” floppy disks were used but these disks
have less storage capacity so new format of 3 1/2”
floppy disk came in market. Now a days floppy disk
are not used because off less storage and high rate.
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52. Optical Disk
This is the secondary storage medium in which you
can store much more data in it. This is flat, circular,
plastic disk coated with material. Optical disk is very
popular because of its small size and huge storage
capacity. You must have optical disk reader in your
computer so that you can read or write data on it.
There are two types of optical disk :-
1. CD
2. DVD
52

53. CD
Known as “Compact Disk”, mainly used to store data,
music, movie, software, etc. it can store 80 minutes of
continues video recording. The space of CD is up to
700 mb. Due to its high storage capacity it is widely
used. The data are store in it is in the form of “Pitts”.
To avail the services of CD your computer should have
CD drive.
There are two types of CD :-
1. CD ROM.
2. CD R/W.
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54. DVD
Known as “Digital Versatile Disk”. It is high capacity
storage medium. Mainly used to store movie, music,
software, etc. the storage capacity of DVD is up to
4.7 gb. It looks similar to CD but due to its high
storage capacity it is not cheaper as CD. To avail the
facility of DVD you must have DVD drive in your
computer. DVD drive also gives you facility to run
CD disks too.
Types of DVD :-
1. DVD ROM.
2. DVD R/W. 54

55. What Is An Input Device ?
Entering data or instructions into a computer is called
input. Therefore, an input device is a device which
enters data or instructions into a computer.
Input devices are necessary to convert data into a
form which can be understood by computers.
Some input devices are:
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56. 56

57. The Mouse
This input device controls the cursor on the computer
screen. It has two or three buttons and a cable
connecting it to the computer. It is quite easy to
operate a mouse, the user simply moves the cursor
along the table. Once the cursor is at the desired
location, the user can give instructions to the
computer by clicking the button.
57

58. The Joystick
A joystick looks like a stick fixed onto a box. It
controls the cursor on the screen, so we can say it is
alternate to the mouse.
The Keyboard
Keyboards come in different shapes and sizes
depending on the type of brand. They are similar to
typewriters.
58

59. The Scanner
This looks like a photocopying machine, its function
is to scan any document placed on its flat glass and
send the contents to the computer.
The Bar Code Reader
The black and white lines printed on certain products
which represent information like the country of
origin, the price of it etc are bar codes. They can be
read by a bar code reader which are commonly used
in Supermarkets and shops.
59

60. What is an Output device?
The information we get from the computer is
known as output. The computer presents this
information through these devices such as:
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61. 61

62. The Monitor
The monitor is one of the most important output devices, it is
used to display text and pictures. The monitor is also known as
the Visual Display Unit (VDU)
The Printer
There are several types of printers, some are:
• Dot matrix- Consists of a print head with a number of pins
which move in and out to print in the form of dots.
• Ink- jet- Consists of a print head with a number of tiny nozzles
and colored ink to form tiny dots.
• Laser- Prints images by transferring ‘ ink powder’ onto a piece
of paper using a laser beam.
62

63. The Plotter
A plotter produces its output using special pens across
the paper to create a drawing. Engineers,
architects and designers use plotters to produce their
drawings or designs.
63

64. REFERENCE
Reference Books
1. Information Technology for Managers By George Reynolds
2. Introduction to Computers by Gary Shelly, Steven Freund, Misty
Vermaat
3. Introduction To Computers (Sie) By Norton
Image Reference
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