Introduction
The term ‘computer’ originates from the word ‘computare’, which means ‘to calculate’. We, human beings, are always in some kind of calculations-simple or complex. Mathematical calculations like addition, subtraction, multiplication, division, etc. can be solved easily with simple tools, mouth, and finger or sometimes we may need formulas, pen, and paper, or calculating machines. Such calculations can be simple, consuming less time to calculate while some calculations can be complex and so difficult that the simple tools, formulas, or methods may not work. Even the calculations may take a long time, and the result can be wrong or inaccurate. Therefore, the man was always in search of a machine that could perform all kinds of calculations faster and more accurately. This gave birth to a machine which is commonly known as a ‘Computer’.
The computer we see today is quite different from the one made in the beginning. The number of applications of a computer, and the speed, and accuracy of calculations have increased. We must appreciate the impact of computers in our day-to-day life. Reservation of tickets on Air Lines and Railways, payment of telephone and electricity bills, deposits and withdrawals of money from banks, business data processing, medical diagnosis, weather forecasting, etc. are some of the areas where the computer has become extremely useful.
However, there is one limitation of computers. Human beings do calculations on their own. But the computer is a dumb machine and it has to be given proper instructions to carry out its calculation. This is why we should know how a computer works.
Some countries are developed, some developing, and others underdeveloped. In the past, many countries which were able to catch up with the opportunities brought about by the industrial revolution became industrialized. Now we are in the process of another industrial revolution. This second industrial revolution is the result of the invention of computer technology. It is one of the greatest inventions of the human mind. Computer technology has been playing important role in every sector of our daily life. The computer has strengthened our capacity in numerical computations, information processing storage, modeling and simulation, the concept of globalization, increasing working capability and efficiency, converting online approach, decreasing physical presence, etc.
A computer, independent of its size, is an electronic device used for processing data (numbers, alphabets, any other symbols). It basically performs the following three functions in sequence
- Receive raw data and instructions from input devices
- Process data according to the instruction,
- Produce useful output, and store information for future use.
The computer is, in fact, a dumb machine in the absence of human intervention. That means, the computer can’t do anything on its own, the user must provide appropriate instructions to the computer in order to generate a useful result. But, once we provide instructions and data, the computer can continue working continuously at a very high speed without any tiredness. If we provide wrong instructions and data, the computer will produce an incorrect result. This is called Garbage in Garbage out (GIGO).
The computer has become an indispensable machine to increase the effectiveness and efficiency of every person, organization, country, student, teacher, scientist, researches, and every field including education, business, industry, science, technology, astrology, mining, astronomy, and many more. The computer can be better understood if we know the technology used in computers and the characteristics and applications of computers. We will discuss characteristics and applications, and evolution in terms of generations of computers, the measurement unit of speed of the computer, classification of computer in terms of size and speed (Micro, Mini, Mainframe, and Super), mobile computing and its applications, computer architecture and organization, components of computer system (Input unit, Processing unit, Output unit, Memory unit), microprocessor and bus system, and hardware interface.
Characteristics of
computer
Nowadays computer is playing an important role in every sector of daily life; it has become a basic need of most people just like television, telephone, or other electronic devices at home, and gaining popularity among others as well. It can solve numerical, logical, or other decision-related human problems very quickly as well as accurately. The important characteristics of a computer are described below:
- Speed: 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 with these circuits at a high speed that is close to the speed of light. The computer can perform millions of operations on the data within a second. The computer generates signals during the operation process therefore the speed of the computer is usually measured in megahertz (MHz) or gigahertz (GHz). It means a million cycles of units of frequency is hertz per second. Different computers have different speeds.
- Accuracy: In addition to being very fast, the computer is a very accurate device. It gives accurate output results provided that the correct input data and set of instructions are given to the computer. It means that output is totally dependent on the given instruction and input data. If input data is incorrect then the resulting output will be incorrect. In computer technology, it is also known as garbage in garbage out.
- Reliability: The electronic components in modern computers have a very low failure rate. The modern computer can perform complicated calculations without problems and produces consistent (reliable) results. In general, computers are very reliable. Many personal computers have needed a service call. Communications are also very reliable and generally available whenever needed.
- Storage: A computer has internal storage (memory) as well as external or secondary storage. In secondary storage, a large amount of data and programs (sets of instructions) can be stored for future use. The stored data and programs are available at any time for processing. Similarly, information downloaded from the internet can be saved on the storage media.
- Retrieving data and programs: The data and programs stored on the storage device can be retrieved very quickly for further processing or use. It is also a very important feature of a computer.
- Automation: A computer can automatically perform operations without interfering with the intervention of the user during the operations. It controls automatically different devices attached to the computer. It executes automatically the program instructions one by one.
- Versatility: Versatile means flexible. Modern computers can perform different kinds of tasks one by one or simultaneously. It is the most important feature of a computer. At one moment you are playing a game on the computer, the next moment you are composing and sending emails, etc. In colleges and universities, computers are used to deliver lectures to the students. The talent of a computer is dependent on the software. Computers can be used in every field like science and technology, automation, education, medicine, e-governance, etc.
- Communications: 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 sent through the internet with the help of a computer. Similarly, telecommunication networks are controlled and switched by computers. It is the most important feature of modern information technology.
- Diligence: A computer can continuously work for many hours without creating any error. It does not get tired while working for many hours. It performs the operations with the same accuracy, reliability as well as speed as the first one.
- No feelings: A 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 the instructions given to them.
