INTRODUCTION TO COMPUTERS!
Computer is a calculating device, which receives input from the user, analyses the input by applying a pre-defined set of instructions to produce output. For instance, in a ticket reservation system, we enter the details of passenger such as name, age, and gender as well as the date of journey as input. The computer then analyses the given data and makes a reservation.
A computer is also called as a data processor, because it can receive, store, process and retrieve any kind of data. For instance, we can use computers to store all the details of employees in an organization, which include personal details, pay details, and leave details. The stored information can be retrieved and used later to analyze the performance of employees and to print pay slips for them.
Computers are everywhere. Every day we come in contact with and use dozens of computers, sometimes without even knowing it. When we stop by the ATM to withdraw cash, a computer performs the calculations, updates our account and mechanical parts controlled by the computer dispense the actual cash; they tell us how much our groceries cost; they provide us with real-time weather reports; driving directions, and in modern vehicles even notify emergency response teams if we're in an accident.
Two important characteristics of a computer are: speed and accuracy. Computers operate at very high speed and execute several million instructions in one second. They also perform their operations with a very high degree of consistent accuracy. Because of these features, computers are used in various fields, where there is a need for doing calculations or data processing speedily, accurately and diligently. Some of the applications of computers are listed below:
- To prepare documents and perform other data processing jobs in offices and homes
- To maintain accounts and transfer funds in banks
- To prepare salary slips in an office
- To reserve tickets in the transportation sector, e.g., Railways, Airlines etc.
- To regulate traffic lights on roads
- To control machines in factories
- To control robotics and modern automobiles
- To design buildings, roads etc.
- To control electronic appliances such as Air Conditioners, TVs, VCRs, etc.
- To forecast weather
- To control and simulate defense equipment
- To perform scientific and industrial research.
Characteristics of Computers
Now-a-days computer is playing a main role in everyday life it has become the need of people just like television, telephone or other electronic devices at home. It solves the human problems very quickly as well as accurately. The important characteristics of a computer are described below:
The computer is a very high speed electronic device. The operations on the data inside the computer are performed through electronic circuits according to the given instructions. The data and instructions flow along these circuits with high speed that is close to the speed of light. Computer can perform million of billion of operations on the data in one second. The computer generates signals during the operation process therefore the speed of computer is usually measure in mega hertz (MHz) or gega hertz (GHz). It means million cycles units of frequency is hertz per second. Different computers have different speed.
2. Arithmetical and Logical Operations
A computer can perform arithmetical and logical operations. In arithmetic operations, it performs the addition, subtraction, multiplication and division on the numeric data. In logical operation it compares the numerical data as well as alphabetical data.
In addition to being very fast, computer is also very accurate device. it gives accurate output result provided that the correct input data and set of instructions are given to the computer. It means that output is totally depended on the given instructions and input data. If input data is in-correct then the resulting output will be in-correct. In computer terminology it is known as garbage-in garbage-out.
The electronic components in modern computer have very low failure rate. The modern computer can perform very complicated calculations without creating any problem and produces consistent (reliable) results. In general, computers are very reliable. Many personal computers have never needed a service call. Communications are also very reliable and generally available whenever needed.
A computer has internal storage (memory) as well as external or secondary storage. In secondary storage, a large amount of data and programs (set of instructions) can be stored for future use. The stored data and programs are available any time for processing. Similarly information downloaded from the Internet can be saved on the storage media.
6. Retrieving data and programs
The data and program stored on the storage media can be retrieved very quickly for further processing. It is also very important feature of a computer.
A computer can automatically perform operations without interfering the user during the operations. It controls automatically different devices attached with the computer. It executes automatically the program instructions one by one.
Versatile means flexible. Modern computer can perform different kind of tasks one by one of simultaneously. It is the most important feature of computer. At one moment your are playing game on computer, the next moment you are composing and sending emails etc. In colleges and universities computers are use to deliver lectures to the students. The talent of computer is dependent on the software.
Today computer is mostly used to exchange messages or data through computer networks all over the world. For example the information can be received or send throug the internet with the help of computer. It is most important feature of the modern information technology.
A computer can continually work for hours without creating any error. It does not get tired while working after hours of work it performs the operations with the same accuracy as well as speed as the first one.
11. No Feelings
Computer is an electronic machine. It has no feelings. It detects objects on the basis of instructions given to it. Based on our feelings - taste, knowledge and experience, we can make certain decisions and judgments in our daily life. On the other hand, computers cannot make such judgments on their own. Their judgments are totally based on instructions given to them.
People often have difficulty to repeat their instructions again and again. For example, a lecturer feels difficulty to repeat a same lecture in a class room again and again. Computer can repeat actions consistently (again and again) without loosing its concentration:
- To run a spell checker (built into a word processor) for checking spellings in a document.
- To play multimedia animations for training purposes.
- To deliver a lecture through computer in a class room etc.
A computer will carry out the activity with the same way every time. You can listen a lecture or perform any action again and again.
Computers are not only fast and consistent but they also perform operations very accurately and precisely. For example, in manual calculations and rounding fractional values (That is value with decimal point can change the actual result). In computer however, you can keep the accuracy and precision upto the level, you desire. The length calculations remain always accurate.