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?

What is long-term, What is long-term, medium-term, short-term? In a bat...

What is long-term, medium-term, short-term? In a batch system many processes are submitted than are able to be executed immediately. These processes are reel to a mass storage

Thread safety, What does it mean for something to be thread-safe? By saying...

What does it mean for something to be thread-safe? By saying that X is thread-safe, we mean that if multiple threads use X at the same time, we don't have to worry about concurrenc

What are the advantages of contiguous allocation, What are the advantages o...

What are the advantages of Contiguous allocation? The advantages are a. Supports direct access b. Supports sequential access c. Number of disk seeks is minimal.

How is memory management done using bit maps?, How is memory management don...

How is memory management done using bit maps? A bit map is here in this we signify the bit value as 0 or 1. 1-hole 0-process In this we are able to represent the proce

Define most common phase structured grammar, Which is most common phase str...

Which is most common phase structured grammar? Most common phase structured grammar is Context – Sensitive

Keeping track of free memory, How do we keep track of where the free pieces...

How do we keep track of where the free pieces of memory are? One idea is to maintain a set of linked-lists of free space; each linked-list will store free chunks of some given size

Cpu, what is cpu

what is cpu

Explain the tlsgetvalue (tlsindex) function, Explain the TlsGetValue (TLSin...

Explain the TlsGetValue (TLSindex) Function Executing this function will return the thread local storage data associated with this thread. The pointer returned will be the one

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