SYSTEM SOFTWARE OF COMPUTER

System software refers to a set of programs that are designed to control the operations of a system. The system software helps all parts of a computer to work together. System software controls all internal operation like reading data from input devices, transmitting information to output devices, checking the components of a computer, etc. System software provide environment for application software in order to run on the computer.
System software may be:
a. Language Processor
b. Operation System Software

a. Language Processor
A computer can only understand instructions written in machine language (i.e. 0s and 1s) directly. However, writing programs in the machine language is very difficult. Therefore, many programming languages have been developed for instructing computers. The process of writing set of instructions in a computer language is called programming. The programs written in assembly and high level languages are needed to translate into machine language so that the computer can understand them.

A Language Processor is a program that converts programs written in any other language into machine language. Language Processor is also known as Translator. The process of converting a program written in a high level or assembly language into machine language is known as Decoding or Translating.
There are three types of Language Processor. They are:
i. Assembler
ii. Interpreter
iii. Compiler

i. Assembler
Assembler is a language processor that translates programs written in assembly language into machine language. A symbolic program written by a programmer in assembly language is called a source program or source code. After the source program has been converted into machine language by an assembler, is referred as an object program or object code.

ii. Interpreter
Interpreter is a program translator that translates programs written in a high level language into machine language. Interpreter translates one statement of a program at a time into machine code and directs to the CPU. After the execution of the first statement, it translates the second statement of a program into machine code and executes it. The translation and execution of each statement of a program is carried out one by one. If any one is found in a statement while translation of a statement, it immediately displays the error message and stops the execution of the program. GWBASIC, QBASIC, LOGO, LISP, etc. are high level languages those use interpreter.

iii. Compiler
Compiler is a language processor that converts program written in a high level language into machine language. The compiler reads whole program at a time and converts it into machine language. A program written by a programmer in a high level language is known as source code or source program. The code that we get after the program is complied by the compiler is known as object code. The process of converting source code into object code is known as compilation. During the compilation of a program errors are listed if they are found.


QuickBasic, Visual Basic, C, C++, Java, etc. are high level programming languages those use compiler.

b. Operating system Software
Operating system Software is the system that controls and manages the overall operation of a computer. Operating system Software is the first software that is loaded into the computer memory (RAM) when you switch on PC on. Operating system Software controls hardware and application software. Operating system Software acts as an interface between the user and the computer or between software and the hardware. Operating system Software provides the environment in which you interact with your computer and application software. Operating system Software is responsible for the smooth and efficient operation of the computer system. Operating system Software is basic requirement of a computer. Without operating system on the computer, we cannot operate the computer.
The main functions of an operating system are given below.

• Operating system controls and manages the hardware present in the computer like microprocessor, input and output devices, etc.
• Operating system manages computer memory (RAM). Operating system assigns the memory to various programs when required and then makes the memory free after the program is not in use.
• Operating system manages files and application programs on a variety of storage media. Operating system performs file related operations such as copying, deleting, moving, and so on.
• Operating system manages software resources of the computer system.
• Operating system create environment to run other software like MS-Word, MS-PowerPoint, Macromedia Flash etc.
• Operating system notifies the user about system errors or errors the encounter during program execution.

Microsoft Disk Operating system errors (MS-DOS), Microsoft Windows 95, Microsoft Windows 98, windows XP, Windows Vista, Apple Macintosh, IBM OS/2, UNIX and LINUX are some examples of operation systems.

Classification of operation system
According to the number of users, operating systems are classified into two types.

a) Single User Operating System
A Single User Operation System is designed to manage a computer so that only one user can work on it at a time. MS-DOS, Windows 98, Windows XP are some examples of Single User Operation System.

b) Multi User Operation System
A Multi User Operation System allows more than one user to access and share the computer system at the same time. UNIX, Windows NT, Windows 2000 Server, Novell Netware etc. are examples of Multi User Operation System.

According to the interfaces, operating systems are classified into two types.
(i) Command Line Interface (CLI) based Operating System
In Command Line Interface (CLI) based Operating System, users are required to type commands to perform any task. MS-DOS and Novell Netware are CLI based operating system.

(ii) Graphical User Interface (GUI) based Operating System
In Graphical User Interface (GUI) based Operating System, icons, buttons, dialog boxes, etc. are provided to interact with the computer. Windows families of operating systems like Windows 95, Windows XP and Windows Vista are GUI based operating systems.