Class DiskScheduler

java.lang.Object
  |
  +--Scheduler
        |
        +--DiskScheduler

public class DiskScheduler

extends Scheduler

A FCFS scheduler for the disk. It maintains a simple queue of jobs.

Constructor Summary

DiskScheduler()

Method Summary

boolean	add(Job j, Job dummy) Add a new job wanting service.
void	printQueue() For debugging: print the queue of waiting jobs
Job	remove() Retrieve (and remove) the next job to be served.
boolean	reschedule(Job j) This method is called when there is a clock interrupt, and just after a job changes state.

Methods inherited from class Scheduler

endBurst, printStats, queueChanged

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

DiskScheduler

public DiskScheduler()

Method Detail

add

public boolean add(Job j,
                   Job dummy)

Add a new job wanting service.

Overrides:

add in class Scheduler

Parameters:

j - the job to serve

dummy - always null

Returns:

false (this scheduler never preempts)

remove

public Job remove()

Retrieve (and remove) the next job to be served.

Overrides:

remove in class Scheduler

Returns:

the next job (null if there is no such job).

reschedule

public boolean reschedule(Job j)

This method is called when there is a clock interrupt, and just after a job changes state.

Overrides:

reschedule in class Scheduler

Parameters:

j - the job currently being serviced by the corresponding device.

Returns:

true if the scheduler wants to preempt the current job.

printQueue

public void printQueue()

For debugging: print the queue of waiting jobs

Overrides:

printQueue in class Scheduler