Linux is one of popular version of UNIX operating System. It is open source as its source code
is freely available. It is free to use. Linux was designed considering UNIX compatibility. Its
functionality list is quite similar to that of UNIX. Some popular versions or distributions of Linux
OS are Ubuntu, Fedora, Linux Mint, openSUSE, PCLinuxOS, Debian etc.
Components of Linux System
Linux Operating System has primarily three components
Kernel − Kernel is the core part of Linux. It is responsible for all major activities of this
operating system. It consists of various modules and it interacts directly with the
underlying hardware. Kernel provides the required abstraction to hide low level
hardware details to system or application programs.
System Library − System libraries are special functions or programs using which
application programs or system utilities accesses Kernel's features. These libraries
implement most of the functionalities of the operating system and do not requires kernel
module's code access rights.
System Utility − System Utility programs are responsible to do specialized, individual
Following are some of the important features of Linux Operating System.
Portable − Portability means software can works on different types of hardware in same
way. Linux kernel and application programs supports their installation on any kind of
Open Source − Linux source code is freely available and it is community based
development project. Multiple teams work in collaboration to enhance the capability of
Linux operating system and it is continuously evolving.
Multi-User − Linux is a multiuser system means multiple users can access system
resources like memory/ ram/ application programs at same time.
Multiprogramming − Linux is a multiprogramming system means multiple applications
can run at same time.
Hierarchical File System − Linux provides a standard file structure in which system
files/ user files are arranged.
Shell − Linux provides a special interpreter program which can be used to execute
commands of the operating system. It can be used to do various types of operations,
call application programs. etc.
Security − Linux provides user security using authentication features like password
protection/ controlled access to specific files/ encryption of data.
The architecture of a Linux System consists of the following layers −
Hardware layer − Hardware consists of all peripheral devices (RAM/ HDD/ CPU etc).
Kernel − It is the core component of Operating System, interacts directly with hardware,
provides low level services to upper layer components.
Shell − An interface to kernel, hiding complexity of kernel's functions from users. The
shell takes commands from the user and executes kernel's functions.
Utilities − Utility programs that provide the user most of the functionalities of an