.. _OSrole:

Basic Operating System Concepts
=================================

What is an Operating System?
-----------------------------

.. index:: operating system

An **Operating system** is basically a intermediary agent between the user
and the computer hardware.

    * Manages the computer's resources (hardware, abstract resources, software)

    * It's a resource allocator.

    * It is also used to control programs to prevent errors and improper
      computer use.

    * It is interrupt driven.

.. figure:: OS_define.png
   :align: center

   Users and Processes access the Computer's resources through the
   Operating System 

Operating System Benefits
--------------------------

* Simplifies hardware control for applications

* Enforcer of sharing, fairness and security with the goal of better overall
  performance

  - Trade-off between fairness and performance

  - Trade-off between optimal algorithms and lean algorithms -- OS is overhead.

* Provides abstract resources

  - Sockets

  - Inter-process communication