Explain various States of the process. - Question & Answer Book

 Answer: - There are a number of states that can be attributed to a process: indeed, the operation of a multiprogramming system can be described by a state transition diagram on the process stats. The states of a process include:

Ø  New- a process being created but not yet included in the pool of executable processes (resource acquisition).

Ø  Ready- processes that are prepared to execute when given the opportunity.

Ø  Active, Running- the process currently being executed by the CPU.

Ø  Blocked, Waiting- a process that cannot execute until some event occurs, such as the completion of an I/O service or reception of a signal.

Ø   Stopped- a special case of blocked where the process is suspended by the user's operator.

Ø  Exiting, Terminated- a process about to be removed from the pool of executable processes (resource release), a process has finished execution and is no longer a candidate for assignment to a processor. Its remaining resources and attributes are to be disassembled and returned to the operating system’s “free” resource structures.

·         As a process executes, it can change state due to either an external influence, e.g., it is forced to give up the CPU so that another process can take a turn, or an internal reason, e.g., it has finished or is waiting for service from the operating system.

·         A process, therefore, takes part in a finite state system, and we typically show this in a state diagram that highlights the conditions necessary to transit from one state to another: