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System Software

Notes 3. Loaders
4. Linkers
5. Macro processors.

1.3.1 Operating System

 It is the most significant system program that performs as an interface among the users
and the system. It makes the computer simpler to utilize.

 It offers an interface that is more comprehensible than the fundamental hardware.
 The functions of OS are: Process management, Memory management, Resource
management, I/O operations, Data management, and offering security to user's job.

1.3.2 Language Translators

Language translator is the program that takes an input program in one language and generates
an output in another language.
Source Program  Language Translator  Object Program

Compiler
Compiler is a program whose job is to accept as input a source program written in a some high-
level language and to generate as output an object code which can be executed on the computer.
A compiler converts programs from one language to the other as displayed in Figure 1.2. It has
a nick name known as translator. Usually, a compiler converts programs written in high-level
language to assembly languages. Assemblers then translate programs written in assembly
languages to machine code. Interpreters such as Java virtual machine executes programs by
interpreting intermediate code like Java bytecode. By and large, a program that converts input
in some form to output in some form can be known as a compiler. There are some fundamental
properties for a compiler.
 A compiler must be error-free.

 A compiler must at all times terminate, regardless of what the input appears like.

!
Caution A compiler should effort to find as many errors as possible throughout a single
compilation pass.

Figure 1.2: Basic Compiler Concept

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