Definition: Operating systems are those programs that interface the machine hardware with the user’s applications programs. The main objective of these is to dynamically allocate the shared system resources to the executing
programs to achieve optimal utilization.

Some of the key points about OS:

• A operating system can be viewed as a resource manager.
• Enforces boundaries among users and processes. Provides protection of hardware from user.
• Enables user to work on system easily.
• Hides complexity of the system from users.
• Provides an abstract view of the system, i.e. a programmer is not required to think of the system level, can write programs easily.

Fig.1: System hardware and software structure

Components of Operating System:

• User Interface
• Kernel
• Hardware Interface

Fig.1: System hardware and software structure

Some of important responsibilities of an operating System.

• Process Management
  • Process Creation
  • Process Termination
  • Process Scheduling
  • Process Synchronization
• Deadlock
• Memory Management
• File Management
• Security
• Device Management
• Control over system performance
• Job accounting