An operating system manages hardware resources and I/O devices to provide services to users. A process is a program running on a computer and is characterized by elements like an ID, state, program counter, and context data stored in a process control block. The dispatcher switches the processor between processes, and a process has a burst time for execution and a limit time for how long it can run.

1. Operating System: An operating system exploits the hardware resources of one or more
processor to provide a set of services to system users. It also manages secondary memory and
I/O devices on behalf of its users. Processor controls the operation of the computer and performs
its data processing functions. When there is only one processor, it is referred as CPU. Process:
There are several definitions about process: A process is a) A program in execution, b) An
instance of a program running on a computer c) A unit of activity characterized by the execution
of a sequence of instructions. d) An entity that consists of a number of elements such as: 1)
Identifier (Process ID) 2) State (waiting, ready, executing) 3) Program counter which has address
of next instruction) 4) Memory pointer points to program code and data associated with this
process. 5) Context data that present in the processor while the process is executing. 6) Input and
Output status information 7) Accounting information includes the amount of processor time and
time limit. Process Control Block stores all elements of a process. Dispatcher: is a program that
switches processor from one process to another. Burst Time is the time required in millisecond
by a process for its execution. Limit time is the time that a process allowed to be executed.