A. Suppose the following disk request sequence (track numbers) for a disk with 200 tracks is given: 95, 180, 34, 119, 11, 123, 62, 64. Assume that the initial position of the R/W head is on track 50. Which of the following algorithms is better in terms of the total head movements for each algorithm? - First Come -First Serve (FCFS) Shortest Seek Time First (SSTF) algorithm

A. Suppose the following disk request sequence (track numbers) for a disk with 200 tracks is given: 95, 180, 34, 119, 11, 123, 62, 64. Assume that the initial position of the R/W head is on track 50. Which of the following algorithms is better in terms of the total head movements for each algorithm? - First Come -First Serve (FCFS) Shortest Seek Time First (SSTF) algorithm

Database System Concepts

7th Edition

ISBN:9780078022159

Author:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Publisher:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Chapter1: Introduction

Section: Chapter Questions

Problem 1PE

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A disk size of 200 tracks receives the requests for the blocks for I/0. operation. No. of blocks requested on disk are: 92, 154, 47, 31, 173, 74, 87, 23. Calculate the total head movements using FCFS and SSTF algorithms. Initially, the head pointer is at 53.
Disk Scheduling Problem: The disk has 200 tracks numbered from 0-199. The head pointer is currently positioned at 112 moving towards track 199. Given the following work queue: 100, 23, 89, 132, 42, and 187, schedule the requests using FCFS, SSTF, SCAN, C-SCAN, LOOK, and C-LOOK by determining the total head movements for each.
Calculate the number of disk tracks traversed using the FCFS, SSTF, SCAN, and LOOK algorithms for the series of disk track service requests given below. At the time the first request arrives in the disk request queue, the read/write head is at track 50, moving toward the outer (lower-numbered) tracks. (Hint: Each track over which the disk arm passes counts in the total, whether or not the track is read.)54, 36, 21, 74, 46, 35, 26, 67
Select the correct answer: The illustration with a request queue (0-199), by using the SCAN algorithm disk scheduling algorithm, Calculate the total head movement in cylinders for 98, 153, 57, 122, 28 and the Head pointer is on 43. O a. 169 Ob. none of them OC. 327 O d. 196 O e., 251
Different algorithms are used for scheduling the disk head so that seek time may be reduced. Calculate a total number of heads movement for the following algorithms for the given numbers of disk cylinders. Shortest Seek Time First (SSTF) b) Circular Look (C-Look) Head Start: 71 Queue: 82 , 153 , 14 , 149 , 6 , 189 , 62 , 99 , 121
Suppose the head of a moving-head disk with 200 tracks numbered 0 to 199 is currently serving a request at track 99 and has just finished a request at track 125. The queue of outstanding requests in FIFO order is: 5, 95, 75, 100,30 and 155. What is the total number of head movements (in cylinders) for the following disk-scheduling algorithms? a.FCFS Scheduling b.SCAN Scheduling c.SSTF Scheduling
A. Suppose the following disk request sequence (track numbers) for a disk with 200 tracks is given: 95, 180, 34, 119, 11, 123, 62, 64. Assume that the initial position of the R/W head is on track 50. Which of the following algorithms is better in terms of the total head movements for each algorithm? - First Come -First Serve (FCFS) Shortest Seek Time First (SSTF) algorithm B. Suggest and discuss two disk scheduling algorithms for the systems that place a heavy load on the disk. Give the reason.
For a 100-cylinder disk, compute the total number of head movements for the request queue provided below, using FCFS scheduling and a 100-cylinder disk (0-99). It is expected that the read write head is present at cylinder number 50 at the start of the program. Request queue for disk cylinders has the following numbers: 75, 25, 30, 68, 40, 89, 10.
DISK SCHEDULING Given the following disk access schedule in terms of the cylinder number compute the seek-distance by using SSTF (shortest seek-time first), and the C-SCAN algorithms. Assume that there are 100 cylinders in total; the current position of the head is 80; the current head movement is downwards (higher to lower cylinder number) Access String: 65, 78, 50, 15, 65, 95, 20, 85
Consider the following disk request sequence for a disk with 100 tracks 54, 25, 76, 85, 10, 50, 77, 43, 61, 21. Head pointer starting at 30 and moving in left direction. 1) Find the number of head movements in cylinders using C-Scan scheduling. 2) Find the number of head movements in cylinders using C-Look scheduling.
. Different algorithms are used for scheduling the disk head so that seek time may be reduced. Calculate total number of heads movement for the following algorithms for the given numbers of disk cylinders. Shortest Seek Time First (SSTF) Circular Look (C-Look) Look Scan C-Scan Current Head Position: 71 Queue: 82, 153, 14, 149, 6, 189, 62, 99, 121 Direction = From current block towards right side
Suppose that a disk drive has 200 cylinders, numbered 0 to 199. The drive is currently serving a request at cylinder 53. The queue of request is kept in the FIFO order: 98, 183, 37, 122, 14, 124, 65, and 67 What is the total number of head movements needed to satisfy these requests for the following SSTF disk-scheduling algorithm? O a. 640 Ob 720 OC 540 O d. 236