Definition of computer
Technically, a computer is a programmable machine. This means it can execute a programmed list of instructions and respond to new instructions that it is given. Today, however, the term is most often used to refer to the desktop and laptop computers that most people use. When referring to a desktop model, the term "computer" technically only refers to the computer itself -- not the monitor, keyboard, and mouse. Still, it is acceptable to refer to everything together as the computer. If you want to be really technical, the box that holds the computer is called the "system unit."
Some of the major parts of a personal computer (or PC) include the motherboard, CPU, memory (or RAM), hard drive, and video card. While personal computers are by far the most common type of computers today, there are several other types of computers. For example, a "minicomputer" is a powerful computer that can support many users at once. A "mainframe" is a large, high-powered computer that can perform billions of calculations from multiple sources at one time. Finally, a "supercomputer" is a machine that can process billions of instructions a second and is used to calculate extremely complex calculations. In short, a device, usually electronic, that processes data according to a set of instructions.Classification of computer
1. The digital computer stores data in discrete units and performs arithmetical and logical operations at very high speed.
2. The analog computer has no memory and is slower than the digital computer but has a continuous rather than a discrete input.
3. The hybrid computer combines some of the advantages of digital and analog computers.
Characteristics of computerNow I will explain each of the characteristic features of a computer in the following headings.
Celerity (High Speed)It denotes the speed of a computer. The computer present in the modern world has the speed of nano and pico second. The various speed that are used by the computers from the former generations are as follows:
1 milli second=1*10^-3 second
1 micro second=1*10^-6 second
1 nano second=1*10^-9 second
1 pico second=1*10^-12 second
Thus the speeds are measured.
AccuracyIt denoted the accuracy of the computer. They are reliable and robust. It ever makes a mistake. Most probably the error occurs due to the user rather than the computer. There may be certain hardware mistake but with the advanced technique in hand they are overcome.
Example: Only accurate robots are used to perform the operations for the patients since human hands are not flexible for making operations.
A computer is free from tiredness, lack of concentration, fatigue, etc. It can work for hours without creating any error. If millions of calculations are to be performed, a computer will perform every calculation with the same accuracy. Due to this capability it overpowers human being in routine type of work.
Spontaneous (Automatic)The computers are automatic. It may execute the process without any intervention of user once they are assigned to a work. Once the data or instruction are fetched from the secondary devices such as optical disks, hard disks etc. Immediately they get stored into RAM (primary memory) and then sequentially they get executed.
Adaptabilty (Versatile)In our day to day life computers has been a part, with their extended flexibility they are used, all over the world. They can be used as personal computers, for home uses, for business oriented tasks, weather forecasting, space explorations, teaching, railways, banking, medicine etc. All Modern computer can perform different kind of tasks simultaneously.
Storehouse (Memory)Secondary storage devices are the key for the data storage. They store the data for which the user wants to retrieve these data for future use. The examples for various secondary devices are Floppy disk, Optical disks (CS and DVD), Zip drives, Thumb drives etc. The data of smaller size can be easily fetched and they can be copied to the primary memory (RAM).
Example: Data Warehousing made by IBM.
Cheaper (Reduction of cost)Computers are short term investment in order to achieve a long term gain. Though the investment is high they reduce the cost of each and every transaction. They reduce man power and leads to an elegant and efficient way for computing various tasks.
Needs a User interfaceThe only draw back of computer is it cannot make the decision of its own. It needs a guidance to enhance the process. After all computers is a machine
Computer is a dumb machine and it cannot do any work without instruction from the user. It performs the instructions at tremendous speed and with accuracy. It is you to decide what you want to do and in what sequence. So a computer cannot take its own decision as you can.
It does not have feelings or emotion, taste, knowledge and experience. Thus it does not get tired even after long hours of work. It does not distinguish between users