Operating System Tutorial

Operating System Tutorial Types of Operating System Evolution of Operating System Functions of Operating System Operating System Properties Operating System Services Components of Operating System Needs of the Operating System

Operating Systems

Linux Operating System Unix Operating System Ubuntu Operating System Chrome Operating Systems Fedora Operating System MAC Operating System MS Windows Operating System Solaris Operating System Cooperative Operating System CorelDRAW Operating System CentOS FreeBSD Operating Systems Batch Operating System MS-DOS Operating System Commercial Mobile Operating Systems

Differences

Difference Between Multi-programming and Multitasking Difference between C-LOOK and C-SCAN Difference between Rotational Latency and Disk Assess Time Trap vs Interrupt Difference between C-SCAN and SSTF Difference between SCAN and FCFS Difference between Seek Time and Disk Access Time Difference between SSTF and LOOK Difference between Process and Program in the Operating System Difference between Protection and Security in Operating System

How To

How to implement Monitors using Semaphores How to Install a Different Operating System on a PC

Questions

What is Kernel and Types of Kernel What is DOS Operating System What is Thread and Types of Thread What is Process Scheduler and Process Queue What is Context Switching What is CPU Scheduling What is Producer-Consumer Problem What is Semaphore in Operating System Monitors in Operating System What is Deadlock What is Paging and Segmentation What is Demand Paging What is Virtual Memory What is a Long term Scheduler What is Page Replacement in Operating System What is BSR Mode What is Convoy Effect What is Job Sequencing in Operating System Why is it critical for the Scheduler to distinguish between I/O-bound and CPU-bound programs Why is there a Need for an Operating System

Misc

Process Management Process State Scheduling Algorithm FCFS (First-come-First-Serve) Scheduling SJF (Shortest Job First) Scheduling Round-Robin CPU Scheduling Priority Based Scheduling HRRN (Highest Response Ratio Next) Scheduling Process Synchronization Lock Variable Mechanism TSL Mechanism Turn Variable Mechanism Interested Variable Mechanism Deadlock Avoidance Strategies for Handling Deadlock Deadlock Prevention Deadlock Detection and Recovery Resource Allocation Graph Banker’s Algorithm in Operating System Fixed Partitioning and Dynamic Partitioning Partitioning Algorithms Disk Scheduling Algorithms FCFS and SSTF Disk Scheduling Algorithm SCAN and C-SCAN Disk Scheduling Algorithm Look and C-Look Disk Scheduling Algorithm File in Operating System File Access Methods in Operating System File Allocation Method Directory Structure in Operating System N-Step-SCAN Disk Scheduling Feedback Queue in Operating System Contiguous Memory Allocation in Operating System Real-time Operating System Starvation in Operating System Thrashing in Operating System 5 Goals of Operating System Advantages of Operating System Advantages of UNIX Operating System Bit Vector in Operating System Booting Process in Operating System Can a Computer Run Without the Operating System Dining Philosophers Problem in Operating System Free Space Management in Operating System Inter Process Communication in Operating System Swapping in Operating System Memory Management in Operating System Multiprogramming Operating System Multitasking Operating Systems Multi-user Operating Systems Non-Contiguous Memory Allocation in Operating System Page Table in Operating System Process Scheduling in Operating System Segmentation in Operating System Simple Structure in Operating System Single-User Operating System Two Phase Locking Protocol Advantages and Disadvantages of Operating System Arithmetic operations in binary number system Assemblers in the operating system Bakery Algorithm in Operating System Benefits of Ubuntu Operating System CPU Scheduling Criteria in Operating System Critical Section in Operating System Device Management in Operating System Linux Scheduler in Operating System Long Term Scheduler in Operating System Mutex in Operating System Operating System Failure Peterson's Solution in Operating System Privileged and Non-Privileged Instructions in Operating System Swapping in Operating System Types of Operating System Zombie and Orphan Process in Operating System 62-bit operating system Advantages and Disadvantages of Batch Operating System Boot Block and Bad Block in Operating System Contiguous and Non - Contiguous Memory Allocation in Operating System Control and Distribution Systems in Operations Management Control Program in Operating System Convergent Technologies in Operating System Convoy Effect in Operating System Copy Operating Systems to SSD Core Components of Operating System Core of UNIX Operating System Correct Value to return to the Operating System Corrupted Operating System Cos is Smart Card Operating System Cosmos Operating Systems Examples Generation of Operating System Hardware Solution in Operating System Process Control Block in Operating System Function of Kernel in Operating System Operating System Layers History of Debian Operating Systems Branches and Architecture of Debian Operating Systems Features and Packages of Debian Operating Systems Installation of Operating System on a New PC Organizational Structure and Development in Debian Operating Systems User Interface in Operating System Types Of Memory in OS Operating System in Nokia Multilevel Paging in OS Memory Mapping Techniques in OS Memory Layout of a Process in Operating System Hardware Protection in Operating System Functions of File Management in Operating System Core of Linux Operating System Cache Replacement Policy in Operating System Cache Line and Cache Size in Operating System What is Memory Mapping? Difference Between Network Operating System And Distributed Operating System What is the difference between a Hard link and a Soft Link? Principles of Preemptive Scheduling Process Scheduling Algorithms What is NOS? What is the Interrupt I/O Process? What is Time Sharing OS What is process termination? What is Time-Sharing Operating System

Feedback Queue in Operating System

In a computer or a laptop, there is a processor which do all the tasks. The processor cannot do all the tasks at a time. So, the tasks will be prioritized and scheduled according to it. This work will be done with the help of Feedback Queues. So, in this article, we are going to study briefly about the Feedback Queue. We will also see their advantages and disadvantages of it.

What is Feedback Queue?

The Feedback Queues was developed by Fernando J. Corbato. The Feedback Queue was introduced in the year 1962. For this, Fernando J. Corbato has received Turing award. The Feedback Queue usually works in multi levels, and they are also called as Multi level feedback Queue. The Feedback Queue works in a sequential order, and it must perform some specific steps. The Feedback Queue firstly divides the processes or tasks into many parts which will be divided as ready queues based on the requirement of processor. The Second step is to prioritize the divided processes or tasks. It gives the processes to the CPU which has high I/O bursts priority and this will be the last and final step of the steps in the Feedback Queue. In the Feedback Queue there will be a method called Round robin and this method will be used in scheduling a foreground queue. The Feedback queue also has another method called FCFS for scheduling the queues that are present in background.

Process of Feedback Queues

  • In the Feedback Queue the processes will run in multiple levels. The first process which starts to run will be considered as the first Queue.
  • The priority of the First Queue will not be altered when it is under process.
  • When the first queue does not finish its process in the given 4 units then the priority will be removed, and the next queue will be prioritized.
  • The queue should be processed in the given time slot otherwise next queue will be prioritized.
  • All the processes that are scheduled will be in the FCFS fashion.
  • The Lower priority queues only come into process when the highly prioritized Queues are empty.
  • The Lower priority queue which is in process will be stopped when the other priority queue is declared.

Advantages of Feedback Queue

There are many advantages in using the Feedback queues and the following are the some of the advantages of Feedback Queues.

  • The Feedback Queues are very flexible in terms of process scheduling and providing the time slots to the prioritized processes.
  • The Feedback Queues allows the processes to switch between the highly prioritized and lowly prioritized processes.
  • It helps in preventing the CPU or processor overloading.
  • In the Feedback Queue there is a mechanism called aging mechanism which helps in moving a lower priority activity to the next higher priority queue.
  • The Feedback Queues also allows the processes to switch in between the queues based on their burst time.

Disadvantages of Feedback Queue

As the Feedback Queues also have some advantages and below mentioned points are the disadvantages in using the Feedback Queues.

  • The Feedback Queues are very complex, and they are not easy to understand.
  • The Feedback Queues are one of the most challenging algorithms in the computer organization.
  • In the Feedback Queues all the methods should require having its own optimum scheduler.
  • When the Feedback queues are used the CPU overheads may be associated with this type of operations.
  • To select the best scheduler, it always depends on the other methods.

Need of using the Feedback queues

The Feedback queues are only used in the task scheduling of the processor. The Feedback queue has got a lot of advantages than any other task schedulers. The Feedback queue method is more adaptable than multilevel queue scheduling method. The Feedback queues have quick response time, and they carry operations like rescheduling a task within short period of time. The Feedback queue method primarily learns from the previous processes, and it also predicts the behavior of the upcoming task or a process. It helps in increasing the reaction time and reduces the time complexity of the process. The turnaround time of the process will also be decreased by using the Feedback queue.