Disk scheduling is a technique operating systems use to manage the order in which disk I/O (input/output) requests are processed. Disk scheduling is also known as I/O Scheduling. The main goals of disk scheduling are to optimize the performance of disk operations, reduce the time it takes to access data and improve overall system efficiency.
In this article, we will explore the different types of disk scheduling algorithms and their functions. By understanding and implementing these algorithms, we can optimize system performance and ensure faster data retrieval.
Importance of Disk Scheduling in Operating System:
Multiple I/O requests may arrive by different processes and only one I/O request can be served at a time by the disk controller. Thus other I/O requests need to wait in the waiting queue and need to be scheduled.
Two or more requests may be far from each other so this can result in greater disk arm movement.
Hard drives are one of the slowest parts of the computer system and thus need to be accessed in an efficient manner.
Key Terms Associated with Disk Scheduling
Seek Time: Seek time is the time taken to locate the disk arm to a specified track where the data is to be read or written. So the disk scheduling algorithm that gives a minimum average seek time is better.
Rotational Latency: Rotational Latency is the time taken by the desired sector of the disk to rotate into a position so that it can access the read/write heads. So the disk scheduling algorithm that gives minimum rotational latency is better.
Transfer Time: Transfer time is the time to transfer the data. It depends on the rotating speed of the disk and the number of bytes to be transferred.
Disk Access Time:
Disk Access Time = Seek Time + Rotational Latency + Transfer Time
