A New Heuristic Disk Scheduling Algorithm

SSRN Electronic Journal, 2019

The objective of this paper is to identify the benefits and drawbacks of the disk scheduling algorithms and proposing an improved algorithm. The performance of a disk drive depends on various factors like seek time, latency time, access time and structure of the disk. This paper covers the comparative analysis of famous disk scheduling algorithms and proposal of a new algorithm with better performance. [1]Since the performance is based on seek time and access time which are dependent on head movement of the disk arm. Therefore, this paper focuses on comparing the head movement of the various algorithms with the new algorithm and concludes on the performance of the algorithms.

International Journal for Research in Applied Sciences and Biotechnology, 2021

In an operating system, disk scheduling is the process of managing the I/O request to the secondary storage devices such as hard disk. The speed of the processor and primary memory has increased in a rapid way than the secondary storage. Seek time is the important factor in an operating system to get the best access time. For the better performance, speedy servicing of I/O request for secondary memory is very important. The goal of the disk-scheduling algorithm is to minimize the response time and maximize throughput of the system. This work analyzed and compared various basic disk scheduling techniques like First Come First Serve (FCFS), Shortest Seek Time First (SSTF), SCAN, LOOK, Circular SCAN (C-SCAN) and Circular LOOK (C-LOOK) along with the corresponding seek time. From the comparative analysis, the result show that C-LOOK algorithm give the least head movement and seek time in different cases as compared to other algorithm. Therefore, it maximizes the throughput for the storage devices.

One of the main goal of the operating system for the disk drives is to use the hardware efficiently. we can meet this goal using fast access time and large disk bandwidth that depends on the relative positions of the read-write head and the requested data. Since memory management allows multiprogramming so that operating system keeps several read/write request in the memory. In order to service these requests, hardware (disk drive and controller) must be used efficiently. To support this in disk drive, the hardware must be available to service the request. if the hardware is busy, we can’t service the request immediately and the new request will be placed in the queue of pending requests. Several disk scheduling algorithms are available to service the pending requests. among these disk scheduling algorithms, the algorithm that yields less number of head movement will remain has an efficient algorithm. In this research paper, we propose a new disk scheduling algorithm that will reduce the number of movement of head thereby reducing the seek time and it improves the disk bandwidth for modern storage devices. Our results and calculations show that, proposed disk scheduling algorithm will improve the performance of disk i/o by reducing average seek time compared to the existing disk scheduling algorithm. For few requests, the seek time and the total number of head movement is equal to SSTF or LOOK scheduling.

This paper aims to discuss the functioning of a disk and the comparative procedure involved in the retrieval of data on a direct access storage device by different algorithms. Efficiency of the different Disk Scheduling algorithms such as First Come First Serve (FCFS), Shortest Seek Time First (SSTF), Scan, Circular Scan (C-Scan) Scheduling algorithm. Disk requests execution and their pros and cons are also provided in this paper in order to make contrasts and comparisons of performance of the said algorithms. This paper also shows the differentiating abilities of the different scheduling algorithms and its effect to storage management, a better analysis of what disk scheduling algorithms do and how these amend the performance of servicing disk requests.

International Journal of …, 2012

Management of disk scheduling is a very important aspect of operating system. Performance of the disk scheduling completely depends on how efficient is the scheduling algorithm to allocate services to the request in a better manner. Many algorithms (FIFO, SSTF, SCAN, C-SCAN, LOOK, etc.) are developed in the recent years in order to optimize the system disk I/O performance. By reducing the average seek time and transfer time, we can improve the performance of disk I/O operation. In our proposed algorithm, Optimize Disk Scheduling Algorithm (ODSA) is taking less average seek time and transfer time as compare to other disk scheduling algorithms (FIFO, SSTF, SCAN, C-SCAN, LOOK, etc.), which enhances the efficiency of the disk performance in a better manner.

TENCON 2000. Proceedings, 2000

Hard disks are being used to store huge informatioddata in all modem computers. Disk drives must provide faster access time in order to optimize speed of I/O operations. In multitasking system with many processes, disk performance can be improved by incorporating a scheduling algorithm for maintaining several pending requests in the disk queue. This paper describes development of a simulator which uses four disk scheduling algorithms (FCFS, SSTF, LOOK for both upward and downward direction, and C-LOOK) to measure their performance in terms of total head movement. Five different types of test samples, containing request tracks from 8 to 50, have been used to obtain simulation results. Developed simulator runs successfully

2009

real-time disk scheduling, storage systems, operating systems, RAID We present a real-time disk scheduling algorithm, Concurrent DS-SCAN (CDS-SCAN), which maximizes throughput for modern storage devices by allowing concurrent I/O requests at the device whenever possible. Past real-time disk scheduling algorithms allowed a single request at a time to go to the storage device, which dramatically reduces the utilization and throughput for modern storage devices, such as RAID arrays and disks with efficient positional-aware scheduling algorithms. We extended the DS-SCAN algorithm so that it can properly account for multiple outstanding I/O requests and guarantee real-time constraints for both outstanding and pending real-time requests. We demonstrate CDS-SCAN's performance on a storage array.

IJARCSMS

To service a request, a disk system requires that the head be moved to the desired track, then a wait for latency and finally the transfer of data.

Since the time movable head disk came into existence, the I/O performance has been improved by proper scheduling of disk accesses. Disk scheduling involves a careful examination of pending requests to determine the most efficient way to service the requests. The two most common types of scheduling are seek optimization and rotational (or latency) optimization. Most of the scheduling algorithms concentrate on reducing seek times for a set of requests, because seek times tend to be an order of magnitude greater than latency times. Some of the most important scheduling algorithms are First-Come-First-Served (FCFS), Shortest Seek Time First (SSTF), SCAN, Circular Scan (C-SCAN) and LOOK. FCFS is the simplest form of disk scheduling algorithm. This algorithm is simple to implement, but it generally does not provide the fastest service. This paper describes an improvement in FCFS. A simulator program has been designed and tested the improved FCFS. After improvement in FCFS it has been found that the service is fast and seek time has been reduced drastically.

Quaid-e-Awam University Research Journal of Engineering Science & Technology, 2021

This review paper compares the various disk scheduling algorithms that are used to schedule processes in a queue, such as FCFS, SSTF, SCAN, C-SCAN, LOOK, C-LOOK, OTHDSA, and Zone Base Disk Scheduling, and then applies all of these techniques to two data sets to assess the performance of each algorithm. The comparison includes updated and improved techniques that show promising results in collecting data from the digital store. The comparison results were also contrasted with supporting the statement that all disk scheduling algorithms' technique offers much better performance. The comparison shows that among all disk scheduling algorithms, OTHDSA has excellent performance and takes a search time of 250 to complete all requests in a queue.