Basic of Computer

What is a computer?

A computer is an electronic device that manipulates information or "data." It has the ability to store, retrieve, and process data. You can use a computer to type documents, send email, and surf the Internet.Computers play an important role in our lives. When you withdraw cash from an ATM, scan groceries at the store, or use a calculator, you're using a type of computer.

Functions of Computer

A typical digital computer consists of:

a) A central processor unit (CPU):The CPU unifies the system. It controls the functions performed by the other components. The CPU must be able to fetch instructions from memory, decode their binary contents and execute them.

b) A memory: The memory serves as a place to store Instructions, the coded pieces of information that direct the activities of the CPU, and Data, the coded pieces of information that are processed by the CPU.

c) Input and output ports:Input and Output operations are similar to memory read and write operations with the exception that a peripheral 1/0 device is addressed instead of a memory location. The CPU issues the appropriate input or output control signal, sends the proper device address and either receives the data being input or sends the data to be output.

Characteristics of Computers

Speed: A computer is a very fast and accurate device. It can process thousands of instructions within a few seconds for which a human being can take several days or months.

Accuracy: Degree of accuracy of the computer is very high. Errors can occur in computerized system also but most of them occur due to human mistakes rather than technical problems is the computer.

Versatility: We can perform many different tasks on the computer. One moment it might be busy in calculating the statistical data of a business organization for annual performance evaluation and at next moment it is capable of working on inventory control.

Permanent Memory: We can store very large amount of information in the secondary storage devices. This information stays with the computer for further use where as humans tend to forget things.

Diligence: Computer is free from problems like exhaustion, lack of concentration, confusion, etc., unlike human beings.

Types of Computers

a) Analog Computers: The analog computer is almost an extinct type of computer these days. It is different from a digital computer in respect that it can perform numerous mathematical operations simultaneously. It is also unique in terms of operation as it utilizes continuous variables for the purpose of mathematical computation. It utilizes mechanical, hydraulic, or electrical energy or operation.

b) Hybrid computers: These types of computers are, as the name suggests, a combination of both Analog and Digital computers. The Digital computers which work on the principle of binary digit system of “0” and “1” can give very precise results. But the problem is that they are too slow and incapable of large scale mathematical operation. In the hybrid types of computers the Digital counterparts convert the analog signals to perform Robotics and Process control.

Computers can be also categorized on the basis of physical structures and the purpose of their use. Based on Capacity, speed and reliability they can be divided into three categories of computers:

1. The Mainframe Computer : These are computers used by large organizations like meteorological surveys and statistical institutes for performing bulk mathematical computations. They are core computers which are used for desktop functions of over one hundred people simultaneously.

2. The Microcomputer : These are the most frequently used computers better known by the name of “Personal computers”. This is the type of computer meant for public use.

3. The Mini computer : Mini computers like the mainframe computers are used by business organization. The difference being that it can support the simultaneous working of up to 100 users and is usually maintained in business organizations for the maintenance of accounts and finances.