How To

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


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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