An operating system is system software which performs the following functions:

1. Processor management, that is, assignment to processors of different tasks being performed by the computer system.

2. Memory management, that is, allocation of main memory and other storage areas to the system programs as well as user programs and data.

3. Input/Output management, that is, coordination and assignment of the different input and output devices while one or more programs are being executed.

4. File management, that is, the storage of files on various storage devices and the transfer of these files from one storage device to another. It also allows all files to be easily changed and modified through the use of text editors or some other file manipulation routines.

5. Coordination and assignment of compilers, assemblers, utility programs and other software to various users of the computer system.

6. Establishment of data security and integrity. That is, ‘it keeps different programs and data in such a manner that they do not interfere with each other, It also protects itself from being destroyed by any user.

7. Facilitates easy communication between the computer system and the computer (human) operator.

8. Maintenance of internal time clock and log of system usage for all the users.

LINUX Operating System: The Linux operating system has three important features:

• The Kernel
• The Shell
• Linux file system

Kernel: The kernel is the core of the Linux system. The kernel controls the sources of the computer, allotting them to different users and tasks. It is loaded in whenever the system is started up referred to as a boot of the system. It will manage the entire resources of the system, presenting them to you and every other user as a coherent system.

The functions performed by the kernel are:

1. Managing the machine’s memory and allocating it to each process.

2. Organising the transfer of data from one part of the machine to another.

3. Accepting instructions from the shell and carrying them out.

4. Enforcing the access permissions that are in force on the file system.

Shell: Linux has a simple user interface called the shell that has the power to provide the services that a user wants. You can see its prompt at the bottom left of your screen. You may enter commands at this prompt. The shell acts as a command interpreter, it takes each command and passes it to the operating system kernel to be acted upon. It then displays the results of this operation on your screen.

The important features provided by the shell are as follows:

• create an environment that meets the user, needs
• write shell scripts
• manipulate the command history
• define-command aliases
• automatically complete the command line
• edit the command line.

There are several different shells available on your system. The most popular shells are bash, pdkash, tesh, zsh, ash.

Linux File System: A file system is a logical method for organising and storing large amounts of information in a way which makes it easy to manage. The file is the smallest unit in which information is stored.

Features of LINUX: 

Following are the features of LINUX:

1. Linux operating system is freely available, which can be loaded in as many machines and as many times as necessary with a single package, without any licence.

2. Linux is a multiuser operating system. Not only can you have many user accounts available on a Linux system, but you can also have multiple users logged in and working on the system at the same time?’

3. In Linux, it is possible to have many programs running at the same time, which means that not only can you have many programs going at once, but that the Linux can itself have programs running in the background.

4. Linux can rely on two working environments, i.e., Shell, i.e., work interface command lines similar to DOS. X-Window, with lots of graphic interface options, including one that is very similar to an improved Windows 95/98.

5. Linux does disk formatting without interfering with the machine’s performance.

6. Linux has strong cryptography which offers you more security.

7. Linux can be installed in several machine profiles without the need to configure the software.

8. Linux operating system is safe from the virus since common users don’t have access to the system’s main kernel.

9. Linux can rely on freely distributed software as well as commercial applications.

10. Linux offers support for a variety of local area network (LAN) boards, modems and serial devices to connect your Linux system to a network.