The document provides an overview of computers, including their definition, history, components, and uses. It defines a computer as an electronic device that processes data, and notes they can perform calculations millions of times faster than humans. The document also describes the basic components of a computer system, including hardware (physical devices) and software (programs). It explains the functions of central processing units, memory, input/output devices, and storage. Finally, it discusses the capabilities of computers in data storage, processing, and input/output.

1. NEETHU NARAYANAN
Asst.Prof
ST. MARY’S COLLEGE

2. CONTENTS
• Overview
• Introduction to Computers
– Characteristics of Computers
– History/Evolution
– Generation Of Computers

3. CONTENTS
• Overview
• Introduction to Computers
– Characteristics of Computers
– History/Evolution
– Generation Of Computers

4. Introduction To Computers
• Definition:
• Its an electronic Device that is used for information
Processing.
• Computer.. Latin word.. compute
• Calculation Machine
• A computer system includes a computer,
peripheral devices, and software

5. Introduction To Computers
• Accepts input, processes data, stores data, and produces output
• Input refers to whatever is sent to a Computer system
• Data refers to the symbols that represent facts, objects, and ideas
• Processing is the way that a computer manipulates data
• A computer processes data in a device called the central
processing unit (CPU)

6. Introduction To Computers
• Memory is an area of a computer that holds data that is waiting to
be processed, stored, or output
• Storage is the area where data can be left on a permanent basis
• Computer output is the result produced by the computer
• An output device displays, prints or transmits the results of
processing

7. Introduction To Computers

8. Introduction To Computers
Computer
Performs computations and makes logical decisions
Millions / billions times faster than human beings
Computer programs
Sets of instructions for which computer processes data
Hardware
Physical devices of computer system
Software
Programs that run on computers

9. • Definition:
• Introduction To Computer Software
• Operating system
• Problem solving Techniques
• Computer Prog ramming languages
• Computer Threats

10. Introduction To Computers
• Capabilities of Computers
• Huge Data Storage
• Input and Output
• Processing

11. Introduction To Computers
• Characteristics of Computers
• High Processing Speed
• Accuracy
• Reliability
• Versatility
• Diligence

12. Information Processing System
• DATA is a collection of independent and
unorganized facts.
• INFORMATION is the processed and organized
data presented in a meaningful form.
• DATA PROCESSING is the course of doing
things in a sequence of steps.

13. Information Processing System
• COMPUTER is an electronic machine that
follows a set of instructions in order that it
may be able to accept and gather data and
transform these into information.

14. PROCESSING
SYSTEM
DATA INFORMATION

15. Functions of an Information Processing
System
1. It accepts and gather data. (INPUT)
2. It processes data to become information.
(PROCESSING)
3. It stores data and information. (STORE)
4. It presents information. (OUTPUT)

16. Three Major Components of an
Information Processing System
• HARDWARE is the tangible part of a computer
system.
• SOFTWARE is the non-tangible part that tells
the computer how to do its job.
• PEOPLEWARE refer to people who use and
operate the computer system, write computer
programs, and analyze and design the
information system.

17. Basic Units of Measurement
• BIT is a unit of information equivalent to the
result of a choice between only 2 possible
alternatives in the binary number system.
• BYTE is a sequence of 8 bits (enough to
represent one character of alphanumeric
data) processed as a single unit for
information.

18. Basic Units of Measurement
• A byte can be used to represent a single
character, which can be:
– A letter
– A number
– A special character or symbol, or
– A space

20. Basic Units of Measurement
• 1,000 bytes =1 kilobyte (K or KB)
1,000 KB =1 megabyte (MB)
1,000 MB =1 gigabyte (GB)
1,000 GB =1 Terabyte (TB)

21. BASIC PC HARDWARE
• HARDWARE is the tangible part of a computer
system.

23. Basic hardware of a PC system
• Central Processing Unit (CPU)
• Memory Unit
• Input Devices
• Output Devices
• Secondary Storage Devices

24. 1. Central Processing Unit
• Brain of the computer.
• It directs and controls the entire computer
system and performs all arithmetic and logical
operations.

25. 2. Memory Unit
• Where the programs and data
are stored .
– READ ONLY MEMORY (ROM)
contains the pre-programmed
computer instructions such as
the Basic Input Output System
(BIOS).
– RANDOM ACCESS MEMORY
(RAM) is used to store the
programs and data that you will
run. Exists only when there is
power.

27. 3. Input Devices
• Allows data and programs to be sent to the
CPU.
– Keyboard
– Mouse
– Joystick
– Microphone
– Webcam
– Scanner
– Monitor

28. Keyboard
• Traditional keyboards
• Flexible keyboards
• Ergonomic keyboards
• Wireless keyboards
• PDA keyboards

29. Two Types of Mouse
• Mechanical - a type of
computer mouse that has a
rubber or metal ball on its
underside and it can roll in
every direction.
• Optical: This type uses a
laser for detecting the
mouse's movement.

30. How a Mouse Hooks Up to a PC
• PS/2 Mouse
• Serial Mouse
• USB/Cordless Mouse

31. Other Pointing Devices
• Trackball
• Track point
• Touch pad
• Touch Screen

32. • Joystick – input device for
computer games
• Light Pens – light-sensitive
penlike device
• Stylus – penlike device
commonly used with tablet
PCs and PDAs.

33. Scanning Devices
• Optical scanners
• Card readers
• Bar code readers
• Character and mark recognition devices

34. Image Capturing Devices
• Digital Cameras
• Digital Video Cameras

35. 4. Output Devices
• Media used by the computer in displaying its
responses to our requests and instructions.
• Monitor
• Audio Speakers
• Printer

36. Types of Monitor
• Cathode Ray Tube (CRT)
• Liquid Crystal Display (LCD)

37. Printers
• IMPACT PRINTERS uses pressure by physically
striking the paper. Ex. Daisy wheel printers,
line printers, dot matrix printers & band
printers.
• NON-IMPACT PRINTER does not apply
pressure on the paper but instead produces
character by using lasers, ink spray,
photography or heat.

38. Dot matrix
printer
Inkjet printerLaser
printer

39. 5. Secondary Storage Devices
• Attached to the computer system to allow you
to store programs and data permanently for
the purpose of retrieving them for future use.
• Floppy disk, Hard disk, CD Rom

40. Floppy Disk
• The most common secondary storage device
• 3.5” disk – 1.44MB

41. High-Capacity Floppy Disks
• Floppy disk cartridges
• 3 ½ inches in diameter
• Stores more information
• Zip disks

42. Hard Disk Drive or Hard Disk
• Made of rigid materials unlike floppy disks
• Holds a greater amount of data

43. Optical Discs
• A standard part of modern desktop machines,
especially used for multimedia purposes and
preferred in loading applications.

44. Kinds
• Blue Ray Disk – 40G
• Digital Versatile Disk
– DVD-R – write once, 3.95G
– DVD RW – rewritable, 3G
– Single Layer and Double Layer
• Compact Disk
– CD-R – write once, 650MB
– CD-RW – rewritable, 700MB

45. Optical Drives
• CD-ROM read CDs
• CD-Writer read/write CDs
• DVD-Combo read/write CDs, read DVD
• DVD Writer read/write CDs
read/write DVDs

46. Other Secondary Storage
• Solid-State Storage
– No moving parts
– Flash memory cards
– USB flash drives

47. Parts that Build Up A System Unit
• Casing or cover
• Power Supply
• Motherboard
• Microprocessor
• Memory
• Video Card
• Sound card
• Floppy disk drive
• Hard disk drive
• CD-ROM drive
• MODEM

48. Casing or cover
• The box or outer shell
that houses most of the
computer, it is usually one
of the most overlooked
parts of the PC.
• Protects the computer
circuits, cooling and
system organization.

49. Power Supply
• Responsible for powering every device in your
computer.
• Parts of a Power supply:
– Disk drive connectors
– Motherboard connector
– Power supply fan
– Power switch
– Input voltage selector
– Cover
– Power plugs receptacle

50. Motherboard
• The physical arrangement in a computer that
contains the computer’s basic circuitry and
components.
• Components are:
– Microprocessor
– (Optional) Coprocessors
– Memory
– Basic Input/Output System (BIOS)
– Expansion Slot
– Interconnecting circuitry

52. Expansion Slots
• Graphic cards
• Sound cards
• Modem cards
• Network interface cards/network adapter

53. Software
• Instructions that tell the computer how to
process data into the form you want.
• Software and programs are interchangeable.
• Two major types:
– System and Applications

54. 2 Kinds of Software
1. System Software enables the application
software to interact with the computer hardware.
– Operating Systems are programs that coordinate
computer resources, provide an interface between users
and the computer; and run applications.
– Utilities perform specific tasks related to managing
computer resources.
– Device drivers are specialized programs designed to
allow particular input or output devices to communicate
with the rest of the computer system.

55. Functions of a System Software
• Managing resources (memory, processing,
storage, and devices like printer).
• Providing user interface
• Running applications

56. 2 Kinds of Software
2. Applications Software - provides the real
functionality of a computer. It help you use
your computer to do specific types of work.
 Basic Applications, widely used in all career
areas.
 Specialized Applications, more narrowly
focused on specific disciplines and
occupations.

57. DOS and GUI Operating System

58. Disk Operating System
• DOS was the first widely installed operating
system for personal computers.
• Command-driven

59. MS-DOS Commands
• A COMMAND is the name of a special
program that makes your computer carry out
a task.

60. Graphical User Interface (GUI)
• Thru GUI, users can interact directly with the
operating system.
• Microsoft Windows
• Icons, Menus, Dialog boxes

62. FILES
• FILE is simply a collection of information that
you store on a disk or diskette.
• Must have a unique name
• Two parts: the filename and extension
separated by a period.
RECIPE.DOC

63. EXTENSIONS
• Use extension to make your filenames more
descriptive.
– .DOC – word documents
– .XLS – excel documents
– .PPT – powerpoint documents

64. DIRECTORIES
• One way of organizing the files on your
computer Hard Disk
• ROOT – one basic directory
• Subdirectories

66. Introduction To Computers
History Of Computers

67. •Before the 1500s, in Europe, calculations were made
with an abacus
Invented around 500BC, available in many
cultures (China, Mesopotamia, Japan, Greece,
Rome, etc.)
•In 1642, Blaise Pascal (French mathematician,
physicist, philosopher) invented a mechanical
calculator called the Pascaline
•In 1671, Gottfried von Leibniz (German
mathematician, philosopher) extended the Pascaline to
do multiplications, divisions, square roots: the Stepped
Reckoner
None of these machines had memory, and they
required human intervention at each step

68. • In 1822 Charles Babbage (English
mathematician, philosopher), sometimes called
the “father of computing” built the Difference
Engine
• Machine designed to automate the computation
(tabulation) of polynomial functions (which are
known to be good approximations of many
useful functions)
– Based on the “method of finite difference”
– Implements some storage
• In 1833 Babbage designed the Analytical
Engine, but he died before he could build it
– It was built after his death, powered by
steam

69. Introduction To Computers
Generations of Computers

70. Introduction To Computers
• Generation of Computers
• First Generation (1946-59)
• Second Generation(1957-64)
• Third Generation(1965-70)
• Fourth Generation(1970-90)
• Fifth Generation(1990 till date)

71. Introduction To Computers
Generation 0: Mechanical Calculators
Generation 1: Vacuum Tube Computers
Generation 2: Transistor Computers
Generation 3: Integrated Circuits
Generation 4: Microprocessors

72. Introduction To Computers
First
Generation
Second
Gen.
Third
Gen.
Fourth Gen.
Technology Vacuum
Tubes
Transistors Integrated
Circuits
(multiple
transistors)
Microchips
(millions of
transistors)
Size Filled Whole
Buildings
Filled half a
room
Smaller Tiny - Palm
Pilot is as
powerful as
old building
sized
computer

73. Introduction To Computers
Some Pictures…..

74. Generation 1 : ENIAC
The ENIAC (Electronic Numerical Integrator and Computer) was unveiled in 1946: the
first all-electronic, general-purpose digital computer

75. The use of binary
In the 30s Claude Shannon (the father of “information theory”) had
proposed that the use of binary arithmetic and boolean logic should be
used with electronic circuits
The Von-Neumann architecture
CPU Memory
I/O
System

76. Generation 2: IBM7094

77. Generation 3: Integrated Circuits
Seymour Cray created the Cray Research
Corporation
Cray-1: $8.8 million, 160 million instructions
per seconds and 8 Mbytes of memory

78. Generation 4: VLSI Improvements to IC technology made it
possible to integrate more and more transistors
in a single chip
SSI (Small Scale Integration): 10-100
MSI (Medium Scale Integration): 100-
1,000
LSI (Large Scale Integration): 1,000-
10,000
VLSI (Very Large Scale Integration):
>10,000
Microprocessors

79. Generation 5?
The term “Generation 5” is used sometimes to refer to all
more or less “sci fi” future developments
Voice recognition
Artificial intelligence
Quantum computing
Bio computing
Nano technology
Learning
Natural languages

81. MEMORY UNIT
• A memory is just like a human brain. It is used to store data and
instructions. Computer memory is the storage space in the
computer, where data is to be processed and instructions required
for processing are stored. The memory is divided into large number
of small parts called cells. Each location or cell has a unique
address, which varies from zero to memory size minus one. For
example, if the computer has 64k words, then this memory unit has
64 * 1024 = 65536 memory locations. The address of these
locations varies from 0 to 65535.
• Memory is primarily of three types −
• Cache Memory
• Primary Memory/Main Memory
• Secondary Memory

82. Cache Memory
• Cache memory is a very high speed semiconductor
memory which can speed up the CPU. It acts as a
buffer between the CPU and the main memory. It is
used to hold those parts of data and program which
are most frequently used by the CPU. The parts of data
and programs are transferred from the disk to cache
memory by the operating system, from where the CPU
can access them.

83. CONT….
• Computer Memory
• Computer Memory can be classified basically into two types:
• 1. Primary Memory
• 2. Secondary Memory
• Primary Memory:
• It is also called as the Main Memory or Internal Memory. It stores the data
for processing and the Program instructions. It is also the Immediate
Access Memory. It is temporary memory and of limited capacity.
• The standard base capacity for Primary memory starts from 640 KB, 1MB,
2MB, 8MB, 128MB, 256MB, 1GB, 2GB, 4GB etc (in multiples of 2).
Depending on the needs of the user.

84. • 1. RAM – Random Access Memory
• It is a read/write memory. Data can be stored by addressing one RAM cell. The data and
programming instructions fed via the input device are stored in the RAM temporarily until that
program is used. RAM may be updated.
• There are 2 types of RAM
• a. Static RAM – It retains the stored information until the computer is working.
• b. Dynamic RAM – It retains stored information only until the progam is working and loses the
information once the program execution is completed.
• 2. ROM – Read Only Memory
• It is a permanent memory. The instructions can only be read by the computer. The instructions
related to system operations are stored here. These instructions are written by the manufacturer
and cannot be edited by the user. When the system is turned ON, ROM instructions are instantly
executed and used in operation of all I/O devices.

85. CONT….
• There are 3 types of ROM
• a. PROM - Programmable Read Only Memory
• It is a non-volatile memory. Instructions can be written once by the programmer and then
subsequently read.
• b. EPROM – Erasable Programmable Read Only Memory
• It is an improvement over the PROM chips. Instructions can be rewritten by the programmer using
special techniques. The instructions are erased using UV light and rewritten. To change the
instructions the chip has to be removed from the machine and then put back after the changes
have been made.
• c. EEPROM – Electronic Erasable Programmable Read Only Memory
• It is advancement over EPROM, and the chip need not be taken out from the machine. Instead the
programming is done using software. These chips are used in Point-of-sale (POS) terminals to
record price related information and can be updated as and when needed. However they are
expensive compared to the normal ROM chips

86. CONT….
• Functions of Primary Memory:
• 1. It holds the OS instructions while the computer is booting.
• 2. It temporarily holds the input instructions from the input devices while the data is being input
and processed.
• 3. It stores the results temporarily until it is transferred to the respective output devices.
• Types of Primary Memory
• 1. RAM – Random Access Memory
• a. Static RAM
• b. Dynamic RAM
• 2. ROM – Read Only Memory
• a. PROM – Programmable Read Only Memory
• b. EPROM – Erasable Programmable Read Only Memory
• c. EEPROM – Electronic Erasable Programmable Read Only Memory
• .

87. CONT….
• Secondary Memory:
• Secondary Memory is memory which stores the data and programming instructions permanently in
the computer system for future use. It could be placed within the computer or connected
externally. Secondary memory is also called Backing Storage Devices or External Storage Devices.
The storage capacity of Secondary Memory is huge and it is permanent in nature. It can also be
regularly updated.
• Data from the Secondary Memory is transferred to the Primary Memory before execution. It is held
there temporarily until the execution process is completed and then transferred to the Secondary
Memory.
• Types of Secondary Memory
• 1. Magnetic Tape
• 2. Magnetic Disk [Floppy Disk, Hard Disk etc]
• 3. Magnetic Drum
• 4. MICR [ Magnetic Ink Character Reader ]
• 5. CD-ROMs
• 6. Pen Drives