Explain the life cycle of a process, Computer Engineering

Explain the life cycle of a process

Each procedure has a life cycle, which consists of execution, creation and termination phases of the procedure.  A method may create several new procedures, which in turn may also generate still new processes, using system calls. In UNIX operating system environment, a new procedure is produced by fork system call. Process creation needs the following four actions:

i) Setting up the process description: Setting up the process description needs the creation of a Process Control Block (PCB). A  Process Control Block contains basic data such as owner, process identification number, process status, explanation of the allocated address space and other completion dependent process specific information needed for procedure management.

ii)   Allocating an address space:  There are only  two ways to allocate address space to processes; allocating separate space to each process or distribution the address space among the created processes.

iii) loading the program into the allocated address space: The executable program file is overloaded into the allocated memory space.

iv)  Passing the process description to the process scheduler:  The process created is then conceded to the process scheduler who distributes the processor to the competing processes.

The process implementation phase is controlled by the process scheduler. Process scheduling may be per process or per thread. The process scheduling involves three concepts: process states, state transition diagram and scheduling policy.

A process may be in one of the following states given below:

  • New: The process is being formed.
  • Running: The process is being implemented on a single or multiple processors.
  • Waiting: The process is to come for some event to occur.
  • Ready: The process is prepared to be implemented if a processor is available.
  • Terminated: The process has completed execution.

At any time a procedure may be in any single of the above said states. As soon as the process is announce into the job line, it goes into equipped state. When the process scheduler transmits the process, its state turn into running. When the process is completely implemented then it is completed and we say that it is in the completed state. However, the process may return to ready state due to some type of interruption or may go to in waiting state because of some I/O activity. When I/O activity is finished it may go to ready state. The state transition diagram shown in figure 3:

                                2250_life cycle of a process.png

The scheduling policy may be both non pre-emptive and pre-emptive. In pre-emptive policy, the process may be distructed. OS had dissimilar scheduling policies. One of the common policies is First In First Out (FIFO) to select the process to be implemented. When the process finished implementation it is terminated by system calls like abort.

Posted Date: 3/1/2013 5:56:58 AM | Location : United States







Related Discussions:- Explain the life cycle of a process, Assignment Help, Ask Question on Explain the life cycle of a process, Get Answer, Expert's Help, Explain the life cycle of a process Discussions

Write discussion on Explain the life cycle of a process
Your posts are moderated
Related Questions
What are Multidimensional Arrays? Multidimensional array: Multidimensional arrays can be defined as "arrays of arrays". For example, a bidimensional array can be fictional as a

Rule in a single direction - equivalences rules: Hence there the power to replace  sub expressions always allows use to prove theorems with equivalences: as given in the above

Find out the two inputs when the NAND gate output will be low. Ans. The output of NAND gate will be low if the two inputs are 11. The Truth Table of NAND gate is shown

Minimax algorithm - artificial intelligence: The minimax algorithm is so called because it assumes that you and your opponent are going to act rationally, so that if you will

Define the Don't Care States - Simplifying K Maps? The Truth table specifications for a logic function may not to include all possible combinations of the input binary digits for

Define cache memory? A special very high speed memory known as a cache is sometimes used to increase the speed of processing by making current programs and data available to th

Question 1 Explain the functional units of a basic computer with a neat diagram 2 What do you mean by addressing modes? List the different types of addressing modes 3 Exp

Why is TCP called end-to-end protocol? TCP is termed as an end-to-end protocol as this provides a connection directly by an application in one computer to an application on a r

List all seven layer of OSI model and describe function of application layer. The layers of OSI model are as follows: (1) The Physical Layer: It defines an interface in

Problem: a) Most RMI and RPC systems expect to be supported by the "Request-Reply Protocol". Describe what "Request-Reply Protocol" is. b) Describe the invocation semantics