This slide is related to the course of MBM first semester, BBA first semester, BBS first semester, MBA first semester, MBS first semester... Introduction to computer system. Prepared by Raj Chand

1. Introduction to Computer System
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2. Definition of Computer
 The word computer is derived from the Latin word computare which means to
calculate, computer is defined as a programmable machine.
 Computer is an electronic machine which accept data from user and process that data
according to predefine d set of instruction and then gives the result.
 Computer is a machine that performs calculations & process information with
astonishing speed & precision.
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3. Importance of Computer
 Computer are important in various ways:
1. Solving Numerical Problems : One of the most important & most difficult jobs performed by
computer is the solution of complicated problems involving numbers.
2. Storing & Retrieving : Information stored in computer is called Database. A computer can search a
huge database quickly o find specific piece of information. The efficiency with which computers store & retrieve
information makes them valuable in a wide range of professions.
3. Creating & displaying documents & pictures : Computer can store a huge number of words
in a way that makes it easy to manipulate them. It gives output in different ways like audio, video , pictures etc.
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4. Characteristics of Computer
 Speed: Computer can do calculation at a very fast rate. It can even perform very complex calculation
that human being may not able to do. Generally the speed of computer is measured in terms of millisecond
, microsecond ,picoseconds and nanosecond.
 Storage: A computer system can store a great amount of data in it. Computers have inbuilt and auxiliary
memory. Any data and information stored in its memory can be retrieved any time as per the need of user.
 Accuracy: If the data and instruction are given by the user is 100% accurate then computer provide
100% accuracy and if the given instruction is not accurate then computer cannot provide 100% accuracy.
 Versatility: The computer is a versatile machine . Computer has ability to communicate with other
systems and adopt several modes like audio-visual, graphics and user-friendly. It means they are used in
different field to operate different applications like education, science and technology.
 Automation: Once we give the appropriate data and instruction a computer can do the operation
automatically as it is already programmed to do so.
 Diligence: A computer is capable of doing required task again and again with out affecting its speed and
accuracy.
 Electronic: Computer totally dependent on electricity. All its parts are totally dependent on electricity,
Even with out power computer cannot boot(start) so igt is known as electronic machine.
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5. Basic terms of Computer
 Hardware: This is the general term used for describing physical parts of
computer, which can be seen and touched. For example CPU , printer ,
monitor , RAM etc.
 Software: This is the term used for describe collection of program ,codes ,
instruction which are designed by software engineer to perform general task
as well as specific task. For example PageMaker , Photoshop etc.
 Program: Program is set of instruction or command which are used to perform
some specific task and certain task.
 Operating System: The operating system is a system software and it is a
interface between computer user and computer hardware, and it is master
controller of all software and hardware. For example Unix ,Linux, mac , vista
etc.
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6. Basic terms of Computer
 Memory: It is computer work space or device where we can store different
types of data and application.
 RAM: It stands for Random Access Memory. It is a temporary memory which
store data and instruction which are currently executed. It is volatile and
virtual memory. The capacity of RAM is measured in KB,MB,GB and TB.
 ROM: It stands for Read only Memory. It is a permanent memory and non
volatile memory. It is used to store predefine instruction which are used to
load the operating system in to main memory(RAM).
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7. Basic terms of Computer
 CPU: It stands for Central processing unit ,it is heart of the computer and
brain of the computer. It has its three components
 ALU
 CU
 Register array
 Microprocessor : A CPU or processor which is built in single chip is called
microprocessor . for example 80286,80386.
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8. Basic terms of Computer
 Firmware: It is a program or instruction written in ROM permanently by the
manufacturers during the manufacturing ROM which is used to load the
operating system in to main memory(RAM).
 Input device: Input devices are those devices which are used to give the
instruction to the computer and they are used to feed the data or instruction.
For example keyboard, mouse ,etc.
 Output device: Output devices are those devices which are used to show the
result . For example monitor, printer.
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9. Advantages of Computer
 Performance given by computer is 100% accurate and it is reliable that any
other devices and human beings
 Comparing with human being it much faster.
 Computer can be very useful in doing repeated jobs which man cannot do.
 Computer is versatile machine as it can do many types of jobs once at a time.
 Computer can be used in different or multiple fields.
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10. Disadvantages of Computer
 Computer is expensive so poor people cannot afford it but day by day it is
becoming cheaper.
 It totally dependent on electricity and if there is no electricity the computer
cannot boot(Start).
 People are becoming to much dependent on computer.
 Computer is dull machine with out users instruction computer cannot do any
thing.
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11. Types of Computer
 On the basis of work
 On the basis of Size
 On the basis of Brand
 On the basis of Model
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12. On the Basis of Work
 On the basis of Work computers are classified in to three types:
1. Analog : Analog computers are those computers which measure physical and
natural value like voltage , temperature, current and pressure. These
computers are works on continuous data only.
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13. On the Basis of Work
 Digital : Digital computers are those computers which count the discount
data only. They convert data in to digit which is (0 and 1) These computer are
much faster then analog computers and far accurate.
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14. On the Basis of Work
 Hybrid : Those computer which is combination of analog and digital
computer it means it can perform both functions which are performed by
analog and digital computer.
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15. Difference Between Analog & Digital
Computers
Analog Digital
Analog computer works
with natural values and
physical values
1 Digital computer works with digits
Accuracy of analog
computer is low
Accuracy of digital computer is high
They do not have there
own memory
They have there own memory
They are used special
purpose only
They used general purpose
Cost of analog computer
is low
Cost of digital computer is high.
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16. On the Basis of Size
 Supercomputer: Supercomputers are most powerful and expensive computer. They
have large storage capacity and processing speed is at least 10 times faster then other
computers. These computers are maintained and operated by computers engineers
only. It can calculate about 400 millions of bytes per second. they are used in ,weather
forecasting, petroleum and medicine etc. for e.g. Cyber 205.
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17. On the Basis of Size
 Mainframe computer: They are medium or large computer made of
several units connected together. They are generally used in big organization
for large scale data processing. there speed is vary from computer ranging to
million of bytes per second..
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18. On the Basis of Size
 Minicomputer: They are like a small mainframe computers. They consist of a few
separate units connected together. These computers can operated by people who is
not computer expert. They can process information at the rate of 4 million bytes per
second. They are used in small organization.
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19. On the Basis of Size
 Micro computer: They are smallest general purpose computer. They are about the
same size of typewriter. They contain small CPU which called microprocessor. They are
used in different area of application like school, college, banking etc.
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20. On the Basis of Brand
 IBM PC: It stand for international business machine . IBM is one of the leading
company of the world in manufacturing mainframe computers. Which was established
in 1924 in USA. The computer manufactured by IBM company is called IBM computer
and . The microcomputer manufactured by IBM company is called IBM PC.
 IBM Compatibles: A computer that has the same functional and characteristics
and principle of IBM computers is called IBM Compatibles. This computer easily run all
the software which run on the IBM pc. These computers are cheaper and popular
because its all parts are easily available in the market.
 Apple and Macintosh: The computer manufactured by Apple company is called
Apple computers. This company was established in 1970 in USA. The apple computer
have there own hardware and software, they does not support other hardware and
software. The advance version of apple computer is called Macintosh.
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21. On the Basis of Model
 XT computer: It stands for Extended Technology. Those computers which have
8086,8088 microprocessor they are called XT computers. There processing speed is
4.77MHz and they cannot run advance version software.
 AT computer: Advance computer. Those computers which have 80286
microprocessor is called AT computers . These computers are faster then XT computer.
They can run advance version of software because they contain more RAM then XT
computers.
 PS/2: Personal system 2.. IBM company started manufacturing next model of
computer in 1990 this model is called ps/2 computer. They are small in size , they can
run any type of software they are portable in size for eg laptop, notebook etc.
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