ihi ths is nilesh mishra

1. INTRODUCTION TO
COMPUTERS

2. What is a Computer
A computer is a programmable machine.
The word “computer” comes from the
word “compute”, which means to
calculate. A computer may be defined as
a device, which operates upon data (Bio-
data of various applicants when the
computer is used for recruiting personnel)

3. Data & Information
The input to computers is data. Data
means facts, the raw material for
information. Data are represented by
symbols, but they are not information
except in a limited sense. Information is
data arranged in an understandable form,
that is useful to the people who receive it.

4. Input-Process-Output Cycle
Every activity follows the pattern of Input-
Process-Output. For every activity, there
is an input, a process and output.

5. Input-Process-Output Cycle
INPUT PROCESS OUTPUT
(Data) Calculating, Sorting, (Information)
Merging, Retrieving
Communicating data

6. COMPUTER PROCESSING OPERATIONS
Essential activities of a data processor :
• Collecting data from various sources
• Converting data into machine readable form
• Reading data into Computer
• Converting data into human readable form
• Distributing data to actual users.

7. CHARACTERISTICS OF COMPUTER
• Automatic
• Speed
• Accuracy
• Diligence
• Versatility
• Power of Remembering
• No I.Q.
• No Feelings

8. Anatomy of Computer
• Computer Hardware
(Computer equipment that is mechanical,
electrical and electronic parts)
• Computer Software
(Programs that instruct a computer how to
process the data and generate reqd infn)
• Computer Heart ware
People who prepares data for computerized
input, write computer programs, monitors
computer operations & distribute the output.

9. Block Diagram of Computer
CPU
Program INPUT Information
• ALU OUTPUT
& Data UNIT (Results)
• CU UNIT
Memory
• Primary
• Secondary
• ALU
• CU CPU components
• Memory Unit

10. Storage Unit
Secondary
Storage
Program
& Input Unit Output Unit Information
Data Result
Primary
Storage
Control Unit
Arithmetic
Logic Unit
Block Diagram of Computer

11. Functional Components of Computer
Hardware of any Computer System can be
classified into :-
• CPU (Central Processing Unit)
Is the brain of the computer system. Responsible
for activating & controlling operations of the
computer System. The CPU functions in a fetch-
execute cycle.
• Peripheral Devices
Input Devices
Output Devices
Data Storage Devices

12. CPU performs :
1. Arithmetic Operations
2. Input-Output Operations
3. Internal data movements
4. Data Manipulation (accepting data, sorting
it,
processing it, generating the results)

13. CPU has various components :
• Arithmetic-logic Unit (ALU)
• Control Unit (CU)
• Memory Unit

14. ALU : Calculations (+, -,/, x,<, >, =, positive, negative
& zero). The output from ALU is fetched by the Control
Unit and sent to various parts of the computer.
Control Unit :
Coordinates the operations of hardware & flow &
execution of data and instructions that are fed into the
memory via CPU.

15. Memory Unit : Also known as the primary storage
or main memory - is a part of the microcomputer that
holds data for processing, instructions for processing
the data (the program) and instructions (processed
data).
It can be divided into primary & secondary memory.
There are several types of memory :
• RAM
• ROM

16. RAM (Random Access Memory)
(a) This is volatile memory.
(b) Its consists of some Integrated circuits chips (IC
Chips) on the motherboard.
(c) Motherboard is designed in such a manner that
its memory capacity can be easily increased by
adding more memory chips in empty memory
slots on the motherboard.

17. ROM (Read only memory)
(a) Non-volatile memory chip.
(b) Data is stored permanently and cannot be
altered by the programmer.
(c) The data stored in ROM chip can be read and
used but cannot be changed.
(d) Essential functions that computer performs
when the computer is switched on, special
programs are written to perform them, called
as microprogram (system boot program)

18. Peripheral Devices
It can be classified as :
• Input Devices
• Output Devices
• Data Storage Devices

19. Input Devices
It can be classified as :
• Keyboard Devices
• Mouse
• Scanner

20. Output Devices
It can be classified as :
• Monitors
• Printers
• Screen Image Projector

21. Evolution of Computer
• 1ST Mechanical machine was invented
by Blaise Pascal in 1642.
• Charles Babbage is considered the
father of modern digital computers.
(19th Century)

22. Well Known Early Computers
• The Mark I Computer (1937-44).
• The Atanasoff-Berry Computer (1939-42)
• The ENIAC (Electronic Numerical Integrator
and Calculator) (1943-46)
• The EDVAC Electronic Discrete Variable
Automatic Computer (1946-52)
• The EDSAC (Electronic Delay Storage
Automatic Calculator) (1947-49)
• The UNIVAC I (Universal Automatic
Computer) (1951)

23. Mini , Micro , Mainframe
computers & their features

24. Classification of computers
• On the basis of size & capabilities
Mini computer
Micro computer
Mainframe computer

25. Micro Computer
• Smallest type of computer , least expensive of all type
• Known as Personal computer
• Introduced by IBM
• Low cost of development
• Arithmetic & control unit combined
• Uses : by single person for single activity
• Microcomputer can be grouped in five categories
Workstation, Desktop, Server , Laptop , Notebooks
• Desktop : used by business people for Word
processing ,spreadsheeting & physically placed on desk.

26. • Workstation : intensive calculation on design such as
architecture & buildings
• Actually, a workstation is a place where work gets done. It
refers to a computer (and often the surrounding area) that
has been configured to perform a certain set of tasks, such
as photo editing, audio recording, or video production. An
office may have several workstations for different purposes,
which may be assigned to certain employees. For example,
one workstation may be used for scanning and importing
images, while another is used for editing images.
Because workstations often work together like in the
example above, they are commonly networked together.

27. Mini Computer
• First introduced in 1960’s
• Faster than micro computer
• More storage space & more input & output devices
• Smaller than mainframe computer
• More expensive
But in general, a minicomputer is a multiprocessing
system capable of supporting from 4 to about 200 users
simultaneously. (they r also used as servers in LANS).
• Business use : Large supermarket

28. Mainframe computer
• More powerful
• More access to input & output device.
• High degree storage
• Can process large volume of data
(More powerful processor)
• Act as host for smaller computers
• Business use : Large overseas Banks

29. The Mark I Computer (1937-44)
Known as Automatic Controlled calculator, this was
the first fully automatic calculating machine
designed by Howard A. Aiken of Harvard University
• Was an electromechanical device
• Developed for punched card machinery.
• It was complex in design & huge in size
• performing addition, subtraction, multiplication,
division at speed of 0.3 sec to add 4.5 sec for
multiply (machine was very slow as compared
to today’s computers).

30. The Atanasoff-Berry Computer (1939-
42)
Electronic machine developed for solving
mathematical equations.
• Used 45 vacuum tubes for internal logic and
capacitors for storage.

31. The ENIAC (1943-46)
The Electronic Numerical Integrator and
Calculator was the first electronic computer.
• Used 18,000 vacuum tubes
• Programs were wired on boards (cant be
changed)
• It took wall space of 20 x 40 square feet room
• addition – 200 microseconds
• Multiplication – 2000 ms.

32. The EDVAC (1943-46)
Electronic Discrete Variable Automatic Computer was
designed on Stored program concept, it was
introduced by Dr. John Von Neumann. It influenced
the modern digital computers.
• Different programs can be loaded and executed
on the same computer.
• storing both instructions & data in binary form
(two digits – 0 & 1 which represents all characters)

33. The EDSAC (1947-49)
Electronic Delay Storage Automatic
Calculator was developed by Britishers. This
machine executed its first program in May
1949.
• addition – 1500 microseconds
• Multiplication – 4000 ms.

34. The UNIVAC I (1951)
The Universal Automatic Computer was the first
digital computer installed in the Census Bureau,
continuously used for 10 years
• First business use - UNIVAC I, was by General
Electrical Corporation in 1954.
• In 1952, IBM Corporation introduced the 701
commercial computer. IBM produced the IBM-
650 and sold over 1000 of these machines.

35. COMPUTER HARDWARE &
SOFTWARE

36. WHAT IS HARDWARE
This includes the computer
equipment that can be seen,
touched (physical entity) and
peripheral devices such as
keyboards, monitors, printers,
floppy drives, pen drives and other
equipment that are connected to
computer

37. COMPUTER SOFTWARE

38. WHAT IS SOFTWARE
Software is a set of programs,
documents, procedures associated
with the operations of a computer
systems.( Computer Instructions &
Data)

39. Computer Software can be divided into :
• System Software
• Application Software

40. System Software
Functions of System Software :
• It supports the development of other
application software.
• Execution of other application software.
• Monitors the effective use of CPU, memory,
peripheral etc.
• It helps the hardware components work together.

41. Types of system software
• Operating systems.
• Utility Programs (Utilities)
• Compilers and Interpreters
(Inbuilt programs)
• Communication software

42. Operating systems
OS software performs basic tasks such as :
• Recognizing input from the keyboard
• Sending output to the display screen
• Keeping track of files & directories on the disk
& controlling peripheral devices.
Most commonly used operating systems are
DOS, Microsoft windows, UNIX, Linux etc.

43. HARDWARE AND SOFTWARE
Hardware Software
Operating System
Pathway between Hardware and Software
A computer can not produce output/results unless
hardware and software works together

44. Utilities Programs (Utilities)
These are a set of programs, which help
users in system maintenance task of routine
nature. For example formatting of hard disk
or floppy disk, taking backup of files stored
on hard disk on to a CD or floppy or pen
drive, creating files. directories, folders etc.

45. Compilers and Interpreters
(Translating Programs)
Computer don’t understand our language. It
only reads machine language. So the
compilers and interpreters are the set of
programs which converts our language into
machine language and process it.
Eg. Spell check, grammar checking in a
word document.

46. Communication software
In Network (where multiple computers are
interconnected together) It enables to
transfer the data and programs from one
computer to another, to share the devices
and data.

47. Application Software
Application software is a set of one or more
programs, to do specific task, to solve
specific problem and to complete the end
user task as per requirement. The
requirement is customized as per our need
and application.
Eg. Ms-Word, Excel, Powerpoint,
Paintbrush, Computer games etc.

48. Most commonly application software are :
• Word-Processing Software
• Spreadsheet Software
• Database Software
• Graphics Software
• Personal Assistance Software
• Education Software

49. Word-Processing Software
It enables us to make use of a computer
system for creating, editing, viewing,
formatting, storing, retrieving and printing
documents.
For eg. letters, reports, books etc.

50. Spreadsheet Software
This software is a numeric data analysis
tool, it allows us to create a kind of
computerized manual ledger having rows &
columns, mostly used by accountants for
keeping a record of financial transactions,
and for preparing financial statements.
For Eg. Payroll, Mark sheet, tracking
stocks & keeping records of investor by
stock brokers.

51. Database Software
• A database software is a collection of
related data stored for information retrieval
purpose. It enables us to create a
database, maintain it (add, delete and
update its records) organize data in
desired format (sort its records
alphabetically name wise)

52. Graphics Software
It enables us to use a computer system for
creating, editing, viewing, storing, retrieving
and printing designs, drawings, pictures,
graphs and anything that can be drawn in
the traditional manner.

53. Personal Assistance Software
It allows us to use personal computers for
sorting and retrieving our personal
information and planning, scheduling, Set
alarms, contacts, financial and inventory of
important items.

54. Education Software
It allows a computer to be used as a
teaching and learning tool. For eg.
Applications are those that teach young
children to do mathematics, recognize
alphabets and to read whole words and
sentences

55. Entertainment Software
It allows a computer system to be used as
an entertainment tool. For eg. Video
games, media player etc.

56. Computer Aided Design (CAD)
It deals with the integration of computers
and graphics design packages for the
purpose of automating the design and
drafting process.

57. OPERATING SYSTEM

58. Operating System
Operating System (OS) is an integrated set of
programs that controls the resources (the CPU,
Memory, I/O devices etc.) of a computer system.
Two main objectives of an operating system are :-
• Making a computer system convenient to use.
• Managing the resources of an operating System:

59. • Making a computer system convenient to
use.
It manages all parts of the system and presents
to the user with an interface or virtual machine,
which is easier to program and use. It hides
the details about the hardware resources from
the programmer and provides the programmer
with a convenient interface for using the
computer system. It acts as an intermediary
between the hardware and its users, providing
a high level interface to low level hardware
resources and making it easier for the
programmer and other user to access and use
those resources.

60. • Managing the resources of an operating
System.
To manage the various resources of the computer
system. It involves keeping track of who is using
which resource, granting resource requests,
accounting for resource usage and mediating
conflicting requests from different users.

61. Single-User Operating System
A single-user operating system provides
access to the computer system by a single
user at a time. If another user needs access to
the computer system, they must wait till the
current user finishes what they are doing and
leaves. We are all familiar with the concept of
sitting down at a computer system and writing
documents or performing some task such as
writing a letter. In this instance there is one
keyboard and one monitor that you interact
with.

62. Multi-User Operating System
When referring to a network, a multi-user
system is a term commonly used to define a
computer capable of allowing multiple users
to connect to a network.
When referring to a computer Operating
System, a multi-user system is a computer
with an Operating system that supports
multiple users at once and/or different times.

63. Disk Operating System (DOS)
DOS is a Program which acts as user-
interface between you, your application
programs and the computer. None of the
programs would work without it, because
DOS controls every part of the computer
system.

64. Disk Operating System (DOS)
DOS is a Program which acts as user-
interface between you, your application
programs and the computer. None of the
programs would work without it, because
DOS controls every part of the computer
system.

65. Process Management
A process (also called job) is a program in
execution. The main objective of the process
management module of operating system is to
manage the process submitted to the system in a
manner to minimize the idle time of the various
processors (CPU, I/O processors, etc.) of the
computer system.