Lucents computer full book notes

              Computer General Introductions 

                                                              Type by:- KESHAV SIR

Introduction:-

A computer is a man made electric machine which stores, reads and process date to produce meaningful information as output. It works very fast and does not make mistakes but it's capacity is limited. It is made of English words 'computer'. It operated under the control of a set of instructions that is stored in its memory units. A computer accepts data from an input device and processes it into useful information which it displays on its outputs device.

Actually, a computer is a collection of hardware and software components that helps us to accomplish many different task. Hardware consists of the computer itself and includes a CPU, a monitor, a keyboard, a mouse and any equipment connected to it. Software is the set of instruction that the computer follows in performing a task. 

Computer and Calculators 

A calculator is a small electric device used for doing mathematical calculations. A calculator can be used to calculate, draw images, write letters, and do many other things as well.

Human Being and computers

Computers cannot work on their own. They do what we want them to do, only we give them the right commands. Its memory is better than human memory, it can't forget anything, it has saved, so it is also called an artificial intelligence.

Comparison between Human beings and Computers 

       Human being                                                 Computer                                                 

Human beings are slow in doing                        Computer can do complex calculations 

calculations.                                                          in seconds.                                                

Human beings cannot remember                        Computers can store and remember a 

Lots of things at one time.                                    large amount of information at one     

                                                                                time.                                                         

Human beings can make mistakes.                    Computers do not make mistakes.        

Human beings have feelings.                               Computers do not have feelings.           

Human beings can think.                                     Computers cannot think.                        

Human beings get tired if they work                   Computers never get tired.                    

for long hours.                                                                                                                        

Elementary words related to computer

Data: Data is information required by the computer to be able to operate or in the other way information we put into the computer is called data. It is gathered from any source but cannot be organized. It cannot be used for decision making. It is a collection of unprocessed items and composition of characters, numbers and symbols collected for a specific purpose. Generally it is divided into three types: numeric data, alphabetic data and alphanumeric data.

1. Numeric Data : Numeric data consists of ten digits 0,1,2,3,4,5,6,7,8,9. There are different types of number system that are used to represent numeric data. These number systems are decimal system, binary number system, octal number system and hexadecimal number system. Examples are examination score, bank balance and pin-code etc.

2. Alphabetic Data: Alphabetic data is used to represent 26 alphabet. It consist of capital letters from A to Z, small letters from a to z and blank space. Alphabetic data is also called non-numeric data. An example of this is, the address of an employee.

3. Alphanumeric Data: Alphanumeric data is used to represent alphabetic data, numeric data, special  characters and symbols. An example of this is, any password.

Information: Information is well organized data which we get after processing of data and it helps un decision making. It is processed data that is organized, meaningful and useful.

Characteristics of a computer

Computer are the foundation of business, travel and leisure of life today. The common characteristics that make computers of all sizes such a powerful machine are speed, accuracy and reliability, storage capacity, ability to operate automatically, diligence, scientific approach and versatility.

1. Speed: Computer provide the processing speed required by all facets of society. The quick service we expect at the bank, at the grocery store, on the stock exchange and on the Internet are dependent on the speed of computers. The speed of a computers is measured in the following time units for the access time or instructions per second.

Millisecond[1ms]                                                     A thousands of a second or 10`3

Micro second [1ms]                                                 A thousand of a second or 10`6

Nano second[1ns]                                                    A million millionth of a second or 10`12

KIPS                                                                         Kilo Instructions Per Second.

MIPS                                                                         Million Instructions Per Second.

2. Accuracy and Reliability: Computers are quite accurate and extremely reliable as well. They are only a machine and do not make errors on their own. Errors are caused by humans, not by computers.

3. High Storage Capacity: Computers are capable of storing enormous amount of data that must be located and retrieved very quickly. The capability to store and retrieve volumes of data is the core of the Information Age.

4. Automation: Once a process has been initiated, it is capable of functioning automatically. It does not require an operator at each stage of the process.

5. Diligence: It is capable of operating at exactly the same level of speed and accuracy even if it has to carry out the most voluminous and complex operations for a long period of time. It does not suffer from physical and mental fatigue, lack of concentration and laziness.

6. Versatility: The wide use of computers in so many areas such as commerce, scientific applications, education in day to day life is ample evidence of its versatility.