What Is Disk Scheduling In Os?

Are you curious to know what is disk scheduling in os? You have come to the right place as I am going to tell you everything about disk scheduling in os in a very simple explanation. Without further discussion let’s begin to know what is disk scheduling in os?

Operating systems are complex software that manage a computer’s hardware and software resources. One crucial aspect of this management is disk scheduling. Disk scheduling is the process by which an operating system decides in what order to service read and write requests from the various processes and users. In this blog, we will explore the concept of disk scheduling in operating systems, its significance, common algorithms, and how it impacts the overall performance of a computer system.

What Is Disk Scheduling In Os?

In modern computing, data storage and retrieval are fundamental operations. Disk scheduling plays a critical role in managing these operations efficiently. Here’s why it’s so significant:

  1. Resource Optimization: Disk scheduling ensures efficient use of the limited disk access time by prioritizing requests and minimizing delays.
  2. Improved Performance: Proper scheduling can significantly enhance the performance of a computer system by reducing seek times and rotational latency, which are the primary factors affecting disk access speed.
  3. Fairness: Disk scheduling algorithms can help maintain fairness in resource allocation. They ensure that no process or user monopolizes the disk, allowing multiple tasks to be executed concurrently.

Common Disk Scheduling Algorithms

Several algorithms have been developed to determine the order in which read and write requests should be serviced. Here are some of the most common disk scheduling algorithms:

  1. First-Come, First-Served (FCFS): This is the simplest disk scheduling algorithm, where requests are serviced in the order they arrive. While it’s easy to implement, FCFS can lead to inefficient disk access, especially if there are long seek times.
  2. Shortest Seek Time First (SSTF): SSTF selects the request with the shortest seek time from the current head position. This approach reduces seek times but may result in starvation for some requests.
  3. SCAN: The SCAN algorithm moves the disk arm from the outermost track to the innermost track, servicing all requests along the way. After reaching the innermost track, it reverses direction and services requests in the opposite direction. This method reduces the seek time for most requests.
  4. C-SCAN: Similar to SCAN, the C-SCAN algorithm moves the arm from the outermost to the innermost track. However, once it reaches the innermost track, it “wraps around” to the outermost track to service any pending requests. This reduces the maximum waiting time for any request.
  5. LOOK: The LOOK algorithm is a more efficient version of SCAN. It only stops at tracks with pending requests and does not visit empty tracks. This approach minimizes seek times without the unnecessary movement of the disk arm.

Impact On System Performance

Disk scheduling algorithms directly impact the overall performance of a computer system. The choice of algorithm can lead to variations in:

  1. Throughput: The number of I/O operations a system can perform in a given time.
  2. Response Time: The time it takes to complete an I/O request.
  3. Fairness: Ensuring that no process is unfairly starved of resources.
  4. Resource Utilization: Maximizing the use of disk resources without overloading the system.


Disk scheduling in operating systems is an essential component of efficient data storage and retrieval. By carefully managing the order in which read and write requests are serviced, these systems can optimize resource utilization, enhance performance, and maintain fairness among multiple processes or users. Different algorithms provide various trade-offs between speed, fairness, and efficiency, allowing operating systems to be tailored to specific needs and workloads. Ultimately, the choice of a disk scheduling algorithm plays a crucial role in how well a computer system can manage its data traffic on the digital highway.


What Is Disk Scheduling?

Disk scheduling and management are essential components of a computer’s operating system that handle the organization and access of data on a disk. Disk scheduling algorithms determine the order in which the read/write head of the disk moves to access data, which impacts the efficiency and speed of accessing data.

What Is Cpu Scheduling And Disk Scheduling?

CPU scheduling makes the system efficient and fas. No. In a multi-user environment all device requests are linked in queues, the seek time is increased causing the system to slow down. Disk Scheduling Algorithms are used to reduce the total seek time of any request.

What Is Scheduling And Types Of Scheduling In Os?

Preemptive Scheduling: Preemptive scheduling is used when a process switches from running state to ready state or from the waiting state to the ready state. Non-Preemptive Scheduling: Non-Preemptive scheduling is used when a process terminates , or when a process switches from running state to waiting state.

What Does Scheduling Means In Os?

Process scheduling is the activity of the process manager that handles the removal of the running process from the CPU and the selection of another process on the basis of a particular strategy. Process scheduling is an essential part of a Multiprogramming operating system.

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