An operating system is a software, or a series of program which performs various types of functions in order to manage
and organize files,”
Functions of an operating system are
(i) Process management
(ii) Memory management
(ii) File management
(iv) Input/output management
An OS can be classified as follows
Allows only one user at a time.
e.g. MS-DOS, Windows 9X.
Allows two or more users to run programs at the same time.
e.g. Unix, Linux, Windows 2000/7
Allows more than one program to be run concurrently.
e.g. Linux, Unix, Windows 95
Supports running a program on more than one CPU.
e.g. Unix, Windows NT/2000.
Used for real-time based applications like satellite launch, weather-forecasting etc.
e.g. Lynx, HP-RT
It is a set of keywords, symbols and a system of rules for constructing statements by which humans can communicate instructions to be executed by a computer. It is mainly categorised as
1. Low level language
These are designed to operate and handle the entire instruction set of a computer system directly which are generally used to write the system software. e.g. machine language and assembly language.
2. Medium level language
It serves as the bridge between hardware and programming layer of a Computer system.
3. High level language
It is not limited to one Computer, designed for a specific job and is easier to understand. e.g. Basic, C, Fortran, Java, Pascal, etc.