An operating system acts as a receptionist, dispatcher, efficiency expert, traffic officer and security guard for your computer.
- It is comprised of a number of managers, such as a hardware manager, network manager etc.
- It effectively allows us to interact with the computer in the way we are used to.
User Interface Management
The user interface management allows the user to input commands into the computer.
This can be done either by a command line interface or a graphical user interface.
- It waits for a user to makes a request.
- It checks if a request is legal based on the user's permissions.
- It determines which software package will handle the request.
- It schedules the software to be run on the computer.
Program Scheduling & Activation
Program scheduling & activation involves the process of running multiple programs on one processor.
- The processor utilization is the percentage of time the processor is busy.
- This process allows the processor utilization to increase as it can run a different process while one is waiting for input.
- The multi-programmed OS allows many programs to be loaded into memory.
If every process has $50\%$ processor utilization, the formula for the processor utilization with $n$ processes is: