How To

What are Operating Systems? or What is an Operating System?

Introduction

Operating System is an interface between User and Hardware and the relation is shown in the picture below:

os and hardware interface

Things handled by the Operating System

Resource Allocating

When we have many programs running simultaneously, we are supposed to allocate:

  1. CPU to some of them.
  2. Memory to some of them.
  3. Input Output to some of them.

These works are done by resource allocator.

NOTE: Sometime resources are sharable but sometime they are not.

Acts as a Manager

It typically manages following things:

  1. Memory
    • Amount of memory you have?
    • How much memory is allocated?
    • What percentage of memory is free?
  2. Processes
    • The states are managed by OS.
  3. Files
    • All the system files present on the secondary storage is managed by OS.
    • Plus any other files from other media source are also managed by Operating System.
  4. Security
    • If a process is given some resource, then at the same time any other process or program cannot use the same resource.

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