Computer

Introduction:

The word COMPUTER can be expanded as Commonly Operating Machine Particularly Used for Trade, Education and Research.

Computer is an electronic machine that can accept data through one of the input devices (such as keyboard, mouse, scanner, joystick, light pen etc.,) and  can process the given data through CPU(Central Processing Unit) and can display the result through one of the output devices (such as monitor, printer).

From this, we can understand that, input devices, CPU and output devices are the major parts of a computer. Here, CPU is the main part. Hence it is called “heart of a computer”.

Computer languages:

A program is usually written in a particular language that is unambiguously understood  and executed by a computer. Thus a computer language is means of communicating with the computer which, being a machine, is receptive only to simple, unambiguous vocabulary. The vocabulary of computer languages are smaller and simpler that natural languages. But they have to be used with great care and precision. The programmer should follow the “grammar” of the computer language strictly. Otherwise, the commands will not be understood by the computer.

Since the invention of the computers, three types of computer language have evolved:

• Machine language
• Assembly language and
• High-level languages

Machine language:

In machine language, all the basic instructions are coded in numeric forms. The location in the computer memory, where a given information is stored, is also numerically coded. Thus, the machine language is complex and tedious. It is very difficult to remember “numeric” machine codes even with a codebook. Because of this, this language usually has led to lengthy, error-prone programs. This has prompted the invention of translators and high level languages.

Assembly language:

In assembly language, instructions, data and addresses are given in “mnemonics”, symbols and labels that are readily  understood by the human brain. This language uses symbolic codes for different operations. Assembly language can be translated into a machine language. A program which performs this translation is called an “Assembler”.

Machine and assembly languages, being machine dependent languages, they are called “low-level “languages.

High-level languages:

The program written in the high-level languages can be run on any computer which support these languages with little or no modifications. The structure of these languages is closer to that of a human language. The sequence of instructions are given using certain specified English words and conventional mathematical notation. The computer cannot directly understand a high-level language. It is translated into machine language before it is executed by the computer. A set of programs used for translation is called a “compiler”

Some of common high-level languages are BASIC, FORTRAN, COBOL, C etc.