What are scheduling queues?, Operating System

Assignment Help:

What are scheduling queues?

Since the processes enter the system they are put into job queue. This queue contains all processes in the system. The processes that are exist in main memory and are ready and waiting to execute are kept on a list called as the ready queue. The queue is in general stored in as a linked list. A ready queue header consist pointer to the first and final PCBs in the list. We extend every PCB to include a pointer that points to the next PCB in the ready queue.

When the process is assigned the CPU, it implements for a while and executes for a while and eventually quits is interrupted or waits for the occurrence of a particular event such as the completion of a request for example the completion of an I/O request. In the case of an I/O request such a request perhaps dedicated tape drive and so on. since the system has several processes, the disk perhaps busy with the I/O request of some other processes.  The process afterward has to wait for the disk. The listing of processes waiting for a particular I/O device queue is called as a device queue.

A new process is originally put in the ready queue. It waits in the ready in anticipation of it is selected fro execution. Formerly the process is assigned to the CPU and is executing one of several events could take place:

  •  
    1. The process could issues I/O request, after that be placed in an i/o queue.
    2. The process could create a new sub process in addition to wait for its termination.
    3. The process could be detached forcibly from the CPU as a result of an interrupt and be put back in the ready queue.

In the first two cases the process finally switches from the waiting state to the ready state and is then put back in the ready queue. A process keep going this cycle until it terminates this cycle until it terminates at which time is removed from all queues and has its PCB and resources deallocated.


Related Discussions:- What are scheduling queues?

Write a note on deadlocks, Write a note on deadlocks. The proper defini...

Write a note on deadlocks. The proper definition of deadlock A set of processes is deadlocked if every process in the set is waiting for an event that only a proces

Cpu, Some CPUs provide for more than two modes of operation. What are two p...

Some CPUs provide for more than two modes of operation. What are two possible uses of these multiple modes?

Define a election algorithm, Consider a setting where processors are not as...

Consider a setting where processors are not associated with unique identifiers but the total number of processors is known and the processors are organized along a bidirectional ri

What is a dispatcher, What is a Dispatcher? The dispatcher is the modul...

What is a Dispatcher? The dispatcher is the module that gives control of the CPU to the process selected by the short- term scheduler. This function includes: Switching

Explain page-replacement algorithms, Q. Consider the following page-replac...

Q. Consider the following page-replacement algorithms. Rank the algorithms on a five-point scale from "bad" to "perfect" according to their page-fault rate. Detach those algorithm

Explain virtual file systems, Virtual file systems The file-system exec...

Virtual file systems The file-system execution having of three major layers. The first layer is the file-system interface, based on the open, read, write and close calls and fi

Requirements for solution of critical section problem, What are the require...

What are the requirements for solution of critical section problems? Mutual exclusion : If process p is implementing in its critical section then no other processes can be exe

What is time-stamping, time-stamping It is a method proposed by Lampor...

time-stamping It is a method proposed by Lamport, used to sequencing events in a distributed machine without the use of clocks. This process is intended to order events consis

Explain how situation can be solved using active directory, Question: a...

Question: a) Windows Server 2003 has brought great enhancements the Server System as compared to the previous version. Write down short notes on the below listed enhancements.

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd