number of sectors per track is 100. Thec timefrom 0 to 99 rotating at 3000 rpm. TheConsider a desk with the 100 tracks umberedto move the head between two successive(a) Consider a set of disk roquests to read(b) Consider an initial set of 100 arbitrarytracks is 02 millisecondsdata from tracks 32. 7, 45, 5 and 10Assuming that the elevator algorithm isused to schedule disk requests and thehead is initially at track 25 moving up(towards larger track numbers), What isthe total seck time for servicing therequests?disk requests and assume that no new direquests arrive while servicing theseroquests. If the head is initially at track 0and the elevator algorithm is used toschedule disk requests, what is the worstcase time to complete all the requests?

Given: A Disk with the 100 tracks numbered from 0 to 99 rotating at 3000 rpm. Number of sector per…

Consider a disk with the 100 tracks Bumbered from 0 to 99 rotating at 3000 rpm The to mave the head between two successive (a) Consider a set of disk requests to read head is initially at track 25 moving up aumber of sectors per track is 100. The ti tracks is 02 milliseconds data from tracks 32, 7, 45, 5 and 10 Assuming that the elevator algorithm is used to schedule disk requests and the (lowards larger track numbers), What is the total seck time for servicing the requests? (b) Consider an initial set of 100 arbitrary disk requests and assume that no new disk requests arrive while servicing these roquests. If the head is initially at track 0 and the elevator algorithm is used to schedule disk requests, what ss the worst case time to complete all the requests?

Consider a disk with the 100 tracks Bumbered from 0 to 99 rotating at 3000 rpm The to mave the head between two successive (a) Consider a set of disk requests to read head is initially at track 25 moving up aumber of sectors per track is 100. The ti tracks is 02 milliseconds data from tracks 32, 7, 45, 5 and 10 Assuming that the elevator algorithm is used to schedule disk requests and the (lowards larger track numbers), What is the total seck time for servicing the requests? (b) Consider an initial set of 100 arbitrary disk requests and assume that no new disk requests arrive while servicing these roquests. If the head is initially at track 0 and the elevator algorithm is used to schedule disk requests, what ss the worst case time to complete all the requests?

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

See similar textbooks

Similar questions

Consider a disk with tracks numbered from 0 to 255. The disk arm is moving towards highnumbered tracks and it takes 1ms to travel from one track to the next adjacent one. While retrieving data from Track 52, the following list of requests has arrived: 185, 17, 124, 83, 40, 29, 76, 112 Identify the disk scheduling algorithms based on the following descriptions: Selects the disk I/O request that requires the least amount of travel from the current position of the disc arm, regardless of direction. The disc arm moves back and forth over the disk, satisfying requests in its path. Based on your answer in (a), perform disk scheduling analysis using these TWO (2) disks scheduling algorithms. Compute the average seek time for both algorithms. Based on your answer in (b), which algorithm performs better disk scheduling? Justify your answer.
Given: Work Queue: 56, 21, 44, 93, 67, 7, 32, 79, 20, 85 Total Cylinder: 0 - 99 Starting position: 25 Solve for the Total Head Movement (THM) for the following Disk scheduling algorithms including the graphical solution (graph as seen on our last lecture): First come, first serve Shortest seek time first Scan Look Circular Scan Circular Look
Devise an efficient divide-and-conquer algorithm for the Towers of Hanoi problem when the disks are colored alternately red and blue, and we add the extra rule that no disk may be placed on any other disk of the same color.
1. In a certain device, the disk rotates at 5000rpm. a) how long does one revolution take? b) what is the average rotational delay of this disk drive 2. Consider a disk dirve with 1000 tracks, numbered 0 to 999. The request queue has the following composition: 300 740 150 940 200 850 145 555 775 695. The current position is 197 and the previous request was served at 100. For each of the following disk scheduling algorithsm, compute the total distance (in tracks) that the disk arm would move. Include the calculation steps in your answers. 2.1 First - In-First-Out (FIFO) 2.2 Shortest - Service-Time - First (SSTF) 2.3 SCAN (no LOOK variation) 2.4 C-SCAN (No C-LOOK variation)
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 disk queue with requests for I/O to blocks on cylinders in that order. Queue = 98, 183, 37, 122, 14, 124, 65, 67 If the disk head is initially at cylinder 53 and direction is Right. FCFS – First-Come, First-Served - FCFS
b) Consider a disk queue with requests for I/O to blocks on cylinders 108, 193, 51, 132, 24, 134, 75, 77. The head is initially at cylinder number 63. The cylinders are numbered from 0 to 199. Find out the total head movements using the following algorithms a) First Come-First Serve (FCFS) b) Shortest Seek Time First (SSTF) c) Elevator (SCAN) d) Circular LOOK (C-LOOK)b) Consider a disk queue with requests for I/O to blocks on cylinders 108, 193, 51, 132, 24, 134, 75, 77. The head is initially at cylinder number 63. The cylinders are numbered from 0 to 199. Find out the total head movements using the following algorithmsa) First Come-First Serve (FCFS)b) Shortest Seek Time First (SSTF)c) Elevator (SCAN)d) Circular LOOK (C-LOOK)
Suppose that a disk drive has 5,000 cylinders, numbered 0 to 4999. The drive is currently serving a request at cylinder 133, and the previous request was at cylinder 115. The queue of pending requests, in FIFO order, is:76,1460, 903, 1764, 938, 1499, 1012,1740,120. Starting from the current head position, what is the total distance (in cylinders) that the disk arm moves to satisfy all the pending requests for each of the following disk-scheduling algorithms? (a) FCFS (b).SSTF (c) SCAN (d) LOOK (e) C-SCAN (f) C-LOOK
suppose that a disk drive has 200 tracks, numbered 0 to 199. The drive is currently serving a request at track 50, and the previous request was at track 20. The queue of pending requests, in FIFO order is, 95, 180, 34,119,11,123,62,64. Starting from the current head position, what is the total distance (in tracks) that the disk arm moves to satisfy all the pending requests, for each of the following disk scheduling algorithms? a. FCFS: b. SSTF
Consider a disk pack with a seek time of 4 milliseconds and rotational speed of 10000 rotations per minute (RPM). It has 600 sectors per track and each sector can store 512 bytes of data. Consider a file stored in the disk. The file contains 2000 sectors. Assume that every sector access necessitates a seek, and the average rotational latency for accessing each sector is half of the time for one complete rotation. The total time (in milliseconds) needed to read the entire file is__?
Suppose the head of a moving head disk with 200 tracks numbered 0-199 is currently servinga request at track 143. It has just finished a request at track 125. If the queue of requests iskept in the FIFO order,86,147,85,177,94,150,102,175,130What is the total head movement to satisfy these requests for the following disk schedulingalgorithms? First Come First Served Shortest Seek Time First SCAN
Given: Work Queue: 56, 21, 44, 93, 67, 7, 32, 79, 20, 85 Total Cylinder: 0 - 99 Starting position: 25 Solve for the Total Head Movement (THM) for the following Disk scheduling algorithms including the graphical solution (graph as seen on our last lecture): Look Circular Scan Circular Look
Suppose Disk drive has 300 cylinders. The current position of head is 90.The queue of pending request is 36,79,15,120,199,270,89,170Calculate head movement for the following algorithms. i) FCFS ii) SSTF