Understand Process Management• Process Scheduling Algorithms                                        1
RecapIn the last class, you have learnt• Priority Scheduling algorithms• Round Robin Scheduling algorithms                ...
HOME     PREVIOUS TOPICNEXTPREVIOUS QUESTION PAPERSFOR OSCPP TUTORIALS                           3
ObjectivesOn completion of this period, you would be able toknow• Multilevel Queue Scheduling• Multilevel Feedback Queue S...
Multilevel Queue Scheduling• This algorithm is used where processes are classified into  different groups• Example :• A di...
Multilevel Queue Scheduling• Separate queues might be used for fore ground & back  ground process• Foreground queue is sch...
Multi Level Queue Scheduling•It separates the CPU processes with different CPU burst characteristics•The processes are per...
Multi Level Queue SchedulingHighest Priority                            System Processes                           Interac...
Multi Level Queue Scheduling• Multi level queue Scheduling algorithm with five queues:  1. System Processes  2. Interactiv...
Multi Level Feedback Queue Scheduling• The idea behind is to separate processes with different  CPU burst characteristics•...
Multilevel Feedback Queue Scheduling•Consider a multilevel feed back queue scheduler withthree queues        q0          q...
Multilevel Feedback Queue Scheduling• Numbered from q0 to q2 as shown in the above fig• The scheduler first executes all p...
Multilevel Feedback Queue Scheduling• This scheduling algorithm gives the highest priority to  any process with a CPU burs...
SummaryIn this class, you have learnt• Multilevel queue scheduling algorithm• Various queues in multilevel queue• Multilev...
Frequently Asked Questions1.   Explain multilevel queue scheduling algorithm2.   List the no of queues in the multilevel q...
Quiz1.   Foreground in multilevel queue scheduling algorithm is     scheduled asa)   FCFSb)   RRc)   SJFd)   None         ...
Quiz2. Background queue in multilevel queue scheduling algorithm is     scheduled asa) FCFSb) RRc) SJFd) None             ...
Quiz3.A process that waits too long in a lower priority queue is     moved to higher priority queue in _________ algorithm...
Quiz4.The processes in multilevel queue algorithm are permanently    assigned to a queue based ona) Memory sizeb) Process ...
Other subject materials•   Web designing•   Micro processors•   C++ tutorials•   javahome
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21 process scheduling alogorithm

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21 process scheduling alogorithm

  1. 1. Understand Process Management• Process Scheduling Algorithms 1
  2. 2. RecapIn the last class, you have learnt• Priority Scheduling algorithms• Round Robin Scheduling algorithms 2
  3. 3. HOME PREVIOUS TOPICNEXTPREVIOUS QUESTION PAPERSFOR OSCPP TUTORIALS 3
  4. 4. ObjectivesOn completion of this period, you would be able toknow• Multilevel Queue Scheduling• Multilevel Feedback Queue Scheduling 4
  5. 5. Multilevel Queue Scheduling• This algorithm is used where processes are classified into different groups• Example :• A division is made between fore ground (interactive) process & back ground ( batch ) processes• Foreground processes have higher priority than background• A multilevel queue scheduling algorithm partitions the ready queue into several separate queues as shown in Fig.1 5
  6. 6. Multilevel Queue Scheduling• Separate queues might be used for fore ground & back ground process• Foreground queue is scheduled by RR• Back ground queue is scheduled FCFS• In addition there must be scheduling among queues• The scheduling used is fixed priority preemptive scheduling• Fore ground queue has priority over background queue 6
  7. 7. Multi Level Queue Scheduling•It separates the CPU processes with different CPU burst characteristics•The processes are permanently assigned to one queue based on following properties -Memory size -Process priority -Process type• Each queue has its own scheduling algorithm 7
  8. 8. Multi Level Queue SchedulingHighest Priority System Processes Interactive Processes Interactive Editing Processes Batch Processes Student ProcessesLowest Priority Fig.1 8
  9. 9. Multi Level Queue Scheduling• Multi level queue Scheduling algorithm with five queues: 1. System Processes 2. Interactive Processes 3. Interactive Editing Processes 4. Batch Processes 5. Student Processes• Each queue has absolute priority over lower priority queues Example: – no process in batch queue could run unless the queues for System, Interactive & Interactive Editing are empty 9
  10. 10. Multi Level Feedback Queue Scheduling• The idea behind is to separate processes with different CPU burst characteristics• If a process uses too much CPU time it will be removed to lower priority queue• This scheme leaves I/O bound & interactive processes in the higher priority queues• A process that waits too long in a lower priority queue is mounted to higher priority queue• Prevents star variations 10
  11. 11. Multilevel Feedback Queue Scheduling•Consider a multilevel feed back queue scheduler withthree queues q0 quantum=8 q1 quantum=16 FCFS q2 11
  12. 12. Multilevel Feedback Queue Scheduling• Numbered from q0 to q2 as shown in the above fig• The scheduler first executes all processes in queue 0• When empty it executes all processes in queue 1 and so on 12
  13. 13. Multilevel Feedback Queue Scheduling• This scheduling algorithm gives the highest priority to any process with a CPU burst of 8 milliseconds or less• In general multilevel feed back queue scheduler is defined by the following parameters: – The number of queues – The scheduling algorithm for each queue – The method used to determine when to demote a process to a lower priority queue – The method used to determine which queue a process will enter when that process need service 13
  14. 14. SummaryIn this class, you have learnt• Multilevel queue scheduling algorithm• Various queues in multilevel queue• Multilevel feedback queue scheduling 14
  15. 15. Frequently Asked Questions1. Explain multilevel queue scheduling algorithm2. List the no of queues in the multilevel queue scheduling algorithm3. Explain multilevel feedback queue scheduling algorithm 15
  16. 16. Quiz1. Foreground in multilevel queue scheduling algorithm is scheduled asa) FCFSb) RRc) SJFd) None 16
  17. 17. Quiz2. Background queue in multilevel queue scheduling algorithm is scheduled asa) FCFSb) RRc) SJFd) None 17
  18. 18. Quiz3.A process that waits too long in a lower priority queue is moved to higher priority queue in _________ algorithm..a) Multilevel queueb) Multilevel feedback queuec) FCFSd) None 18
  19. 19. Quiz4.The processes in multilevel queue algorithm are permanently assigned to a queue based ona) Memory sizeb) Process priorityc) Process typed) All the above 19
  20. 20. Other subject materials• Web designing• Micro processors• C++ tutorials• javahome

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