Concept and Characteristics of Computer – Computer Science – Grade XI
The word “Computer” comes from the word “Compute”, which means, “to calculate”. To calculate the means to do some mathematical operations. It consists of the devices to enter data, process it, store it and give results. Data refers to the raw facts and figures. Today it has become a powerful tool for human beings because of its high utility and versatility. It has become necessary in every field of today’s world like home, school, scientific world etc.
More accurately, we can define a computer as a device that operates upon data. Data can be anything like marks obtained by a student in various subjects when used for preparing results; details (name, age, sex etc) of passengers when used for making airline or railway reservations, or a number of parameters when used for solving any mathematical or scientific calculations, etc.
Thus, a computer is an electronic machine that can store, process and retrieves data when desired. So, the computer is also called the data processor because it processes the raw data and gives meaningful information. The activity of processing data by using a computer is called data processing. Information is the processed data obtained with a specific meaning. In another word, a computer can be considered as an information processing machine.
The basic computer processing is as
A computer can store a large amount of information; you can retrieve them whenever needed. The computer can understand only electric signals ON and OFF where ON means the circuit is on and OFF means the circuit is off. Thus, a computer is an electronic device that processes the input data according to the given set of instructions to give a meaningful output or information.
Characteristic of Computer
The increasing popularity of computer has proved that it is a very powerful and useful tool. The power and usefulness of this popular tool are mainly due to the following characteristics:
Computers are automatic machines because once started on a job, they carry out the job without any human intervention until it is finished. However, computers being machines cannot start themselves and cannot go out and find their own problem and solutions. Users need to instruct the computer what to do.
Computers can work very fast. It can perform any calculation in a few milliseconds. A computer can do a job in a few minutes that would take a man in his entire lifetime. While talking about the speed of the computer, we do not talk in terms of seconds or even milliseconds (10-3) but in terms of microseconds (10-6), nanoseconds (10-9) or even in picoseconds (10-12).
Difference measuring functions of a second have listed below:
|Unit of Time||Part of seconds||Meaning|
|Milliseconds (ms)||1/1000 of a second||Thousand of a second|
|Microseconds (us)||1/ 1000000 of a second||Millions of a second|
|Nanoseconds (ns)||1/ 1000000000 of a seconds||Thousand millions of a second|
|Pico seconds (ps)||1/ 1000000000000 of a second||Million millionths of a second|
|Femto second||1/ 10000000000000000 of a second||Billion millionths of a second|
In addition to being fast, computers are very accurate. The accuracy of a computer is consistently high and the degree of accuracy depends upon its design. A computer performs any calculation with the same accuracy. However, errors may occur on a computer. These errors are mainly due to human beings rather than a computer. An error may occur due to any incorrect data entered by the user. If the input data are incorrect and the entered instructions are unreliable then the result produced by the computer will be undesired. This is known as garbage-in-garbage-out (GIGO).
Unlike human beings, a computer is free from monotony, tiredness, and lack of concentration. It can continuously work for hours without creating any error and without grumbling. To performs calculations with the same accuracy and speed as it has done in the first one. If ten million calculations have to be performed, a computer will perform the last on with exactly the same accuracy and speed as the first one.
Computers are versatile machines. Versatility is one of the wonderful features of a computer. It can perform any kind of operations at enormous speed. A computer is capable of performing any kind of task if the task can be reduced to a finite number of series.
A computer contains a very large storage space. It can store a huge amount of data and information in a small space and make it accessible immediately and correctly when desired. There are two main types of memory in a computer- main memory and secondary memory. The main memory is used to store a small amount of data and information though it contains a small space. Secondary memory that is also called storage is used to store a large amount of data and information. Secondary storage is a hard disk, CDROM, DVDROM, magnetic tape etc. The storage capacity of a computer is measured in bits.
|0 or 1||1 bit|
|4 bits||1 nibble|
|8 bits||1 byte|
|1024 bytes||1 kilobyte|
|1024 kilobytes||1 megabyte|
|1024 megabytes||1 gigabyte|
|1024 gigabytes||1 terabyte|
Limitations of computer
As we discussed the various characteristics of the computer above. Despite its various features, a computer does have the following limitations.
- Acomputer does not have self-intelligence so it is like a dull machine & cannot think itself like a human being.
- The computer does not have decision making power so it cannot change the steps of processing itself.
- Computer cannot learn from past experience as a human can.
- The computer needs electricity or power backup to operate.
- The computer cannot work without a set of instructions or program.
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