An operating system manages computer hardware resources and provides common services that allow application programs to function. It performs key tasks like processor management, memory management, file management, and device management. Operating systems can be interactive with graphical user interfaces, real-time to react within a time period, or distributed across networked computers. Popular examples of operating systems include versions of UNIX, Linux, Windows, Android, and Solaris.

2.  An operating system (OS) is software that
manages computer hardware resources and
provides common services for computer programs.
The operating system is an essential component of
the system software in a computer system.
Application programs usually require an operating
system to function.
 Time-sharing operating systems schedule tasks for
efficient use of the system and may also include
accounting software for cost allocation of processor
time, mass storage, printing, and other resources.

3.  PROCESSOR MANAGEMENT : It keep track of
the processor by recoding whether the processor is
busy , and if so , who is using it.
 MEMORY MANAGEMENT : It keeps track of the
memory by recoding which memory space in use
by which program and which space is free.
 File management : An operating system organizes
and keeps track of files, i.e., which files are in use
and by which jobs.
 DEVICE MANAGEMENT : It keeps track of the
input and output devices , i.e., which devices is in
use and by which job.

4.  INTERATIVE : An interative operating system
uses a graphical user interface .
 REAL TIME : A real-time operating system is a
computing environment that reacts to input
within a specific time period.
 DISTRIBUTED : A distributed operating
system is a control program that runs on a set
of computers which are interconnected by a
network .

5.  UNIX : UNIX was developed by a small group of
programmers at AT&T Bell Laboratories in 1969.
 LINUX : It is a UNIX –like operating system
designed for personal computers .
 WINDOWS : It is a operating system developed by
Microsoft.
 SOLARIS: It is a UNIX operating system originally
developed by Sun Microsystems.
 BOSS(Bharat Operating System olution) : It is a
GNU/Linux distribution developed by C-DAC,
Chennai, to facilitate the use of free/open-source
software throughout India.

6.  ANDROID : It is n operating system used in
mobile phones and tablets. It is owned and
maintained by Google Inc.
 WINDOWS 8 : It is an operating system that
has a version for mobile phones. Released on
October 26 2012, it is owned and maintained by
Microsoft.