Page 31 - Viva ICSE Computer Studies 5 : E-book

Language Processor

We give instructions to computer using a language. A set of instructions is called
a program and the language using which we give the instructions is called the
programming language or computer language or simply language. There are many

types of computer languages such as machine language and high-level language.
Although we can give instructions to computer using any language, internally it
understands only the machine language. The machine language consists of two

numbers only, i.e., 0s and 1s. Regardless of the programming language used (except
machine language), the symbolic instructions have to be translated into a form that can
be executed by computer. The software which converts the codes of other languages

into machine code are collectively called language processors. Language processors are
categorised into three types—interpreters, compilers and assemblers.

Interpreters
Instructions of a high-level language are coded in many statements. At the time of their
execution, they are converted statement by statement into machine code by using a
system software called interpreter. There are certain disadvantages of interpreters.

As instructions are translated and executed simultaneously using interpreters, they are
very slow for executing large programs. Hence, interpreters are not suitable for most
application developments.

Compilers
In contrast to interpreters, compilers provide faster execution speed. Compilers do
not translate and execute the instructions at the same time. They translate the entire

program (source code) into machine code (object code) at one time. Using linker,
the object code is converted into executable code. As compared to interpreters or
assemblers, compilers are preferred in the development of application software.

Assemblers
Assemblers translate the assembly language code called mnemonic code (source
program) into machine language code (object program). After assembling, a linker

program is used to convert the object program into an executable program. Assemblers
are used mainly in the development of system software.

Application Software

Application software consists of programs that are required to perform specifi c type
of work for end users on computer. They are required for general and special purpose

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