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Recent questions tagged disk-scheduling

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GO Classes Test Series 2024 | Mock GATE | Test 14 | Question: 62
At a particular point in time, the buffer cache has dirty data that needs to be flushed to disk. Suppose that the identities of these blocks can be listed in [track:sector] form as follows: ... Shortest Seek Time First Scan (initially moving upwards) Look (initially moving upwards) C-SCAN (initially moving upwards)

GO Classes asked in CO and Architecture Feb 5

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5 votes

1 answer

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GO Classes Test Series 2024 | Mock GATE | Test 11 | Question: 43
Consider the following $6 \;\mathrm{I} / \mathrm{O}$ operations and their respective cylinder locations on disk. Seek time is $0.1$ milliseconds per cylinder traversed. The cylinders are numbered from $0$ to $99.$ ... total time we spend seeking is $\mathrm{Y}$ milliseconds. What is $10 \ast(\mathrm{X}-\mathrm{Y})?$

GO Classes asked in CO and Architecture Jan 13

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Find seek time using FCFS,SSTF, SCAN.C-SCAN, LOOK for the following string 98, 183, 37, 122, 14, 124, 65, 67 Assume that request queue (0-199).and Head pointer 53

aritrik7849 asked in Operating System Nov 24, 2023

491 views

2 votes

1 answer

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DRDO CSE 2022 Paper 2 | Question: 8
If the disk head is initially located at track $32,$ find the number of disk moves required with First Come First Serve $\text{(FCFS)}$ scheduling criteria if the disk queue of $\text{I/O}$ blocks requests are: $90 \; 77 \; 24 \; 104 \; 55 \; 87.$

admin asked in Operating System Dec 15, 2022

by admin

516 views

4 votes

1 answer

5

GO Classes Test Series 2023 | Operating Systems | Test 4 | Question: 13
Given a disk with $200$ tracks, where track requests are received in the following order $55, 58, 39, 18, 90, 160, 150, 38, 184.$ The starting position for the arm is track $100.$ What is the number of tracks crossed when the elevator algorithm, starting in the direction UP, algorithm is used?

GO Classes asked in Operating System Oct 9, 2022

388 views

2 votes

1 answer

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Applied Test Series
A disk drive has 5000 cylinders, numbered 0 to 4999. The drive is serving a request at cylinder 143 currently and the previous request was at 125. The disk I/O queue, in FIFO order, is 86, 1470, 913, 1774, 948, 1509, 1022, 1750, 130 ... the current head position, what is the total distance (in cylinders) that the disk arm moves to satisfy all the pending requests, for SCAN?

LRU asked in Operating System Dec 28, 2021

by LRU

4.0k views

1 vote

1 answer

7

Live Test Series Live: Applied
We are given a hard disk of 500 GB. The performance details are : 5000 RPM rotation rate 200 cylinders, numbered from 1 to 200 Takes 1 + (n/20) milliseconds to move heads across n cylinders (e.g., from i to i + n). A ... the head travels half the cylinders and half a revolution. The average time taken to read a 1MB block from the hard disk is__? Need help.

ramakrushna asked in CO and Architecture Dec 22, 2021

781 views

2 votes

1 answer

8

Applied Grand Test 2
Given a disk with 100 cylinders (0 to 99). Exactly one time unit is required to move the read/write head from one cylinder to the next. At time 0 the heads are at cylinder 0 and no requests are pending. The following six requests ... of the heads in movement. Assuming, that rotational and transfer times are negligible, the total time required for the Scan algorithm is _____

LRU asked in Operating System Nov 22, 2021

by LRU

871 views

2 votes

2 answers

9

Applied Test Series
In a system SCAN, disk scheduling policy has been used. The number of tracks traversed by the head if the disk has 200 tracks and the requested tracks, in the order received, are 65, 48, 39, 08, 99, 164, 152, 38, 124 PS : Assume initial head position is at 65, and it will move towards 0

LRU asked in Operating System Oct 20, 2021

by LRU

523 views

1 vote

3 answers

10

UGC NET CSE | October 2020 | Part 2 | Question: 16
Consider a disk system having $60$ cylinders. Disk requests are received by a disk drive for cylinders $10,22,20,2,40,6$ and $38$, in that order. Assuming the disk head is currently at cylinder $20$, what is the ... one and Shortest Seek Time First (SSTF) algorithm is used? $240$ milliseconds $96$ milliseconds $120$ milliseconds $112$ milliseconds

go_editor asked in Operating System Nov 20, 2020

2.4k views

0 votes

3 answers

11

NIELIT 2017 OCT Scientific Assistant A (CS) - Section B: 35
Disk request come to a disk driver for cylinders in the order $10,22,20,2,40,6$ and $38,$ at a time when the disk drive is reading from cylinder $20$. The seek time is $6\text{ ms}$ per cylinder. The total seek time, if the disk arm scheduling algorithm is first-come-first-served is $900$ ms $850$ ms $360$ ms $876$ ms

admin asked in Operating System Apr 1, 2020

by admin

1.0k views

0 votes

1 answer

12

NIELIT 2017 July Scientist B (CS) - Section B: 35
A disk has $200$ tracks (numbered $0$ through $199$). At a given time, it was servicing the request of reading data from track $120$, and at the previous request, service was for track $90$. The pending requests (in order of their arrival) are for track numbers. ... ) and FCFS (First Come First Serve)? $2$ and $3$ $3$ and $3$ $3$ and $4$ $4$ and $4$

admin asked in Operating System Mar 30, 2020

by admin

866 views

1 vote

6 answers

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UGC NET CSE | January 2017 | Part 3 | Question: 50
Consider a disk queue with I/O requests on the following cylinders in their arriving order: $6,10,12,54,97,73,128,15,44,110,34,45$. The disk head is assumed to be at cylinder $23$ and moving in the direction of decreasing number of ... in the disk is $150$. The disk head movement using SCAN -scheduling algorithm is: $172$ $173$ $227$ $228$

go_editor asked in Operating System Mar 24, 2020

4.6k views

8 votes

1 answer

14

GATE CSE 2020 | Question: 35
Consider the following five disk five disk access requests of the form (request id, cylinder number) that are present in the disk scheduler queue at a given time. $(P, 155), (Q,85), (R,110),(S, 30), (T,115)$ Assume the head is positioned at ... ,but before $T$. The head reverses its direction of movement between servicing of $Q$ and $P$. $R$ is serviced before $P$.

Arjun asked in Operating System Feb 12, 2020

by Arjun

5.2k views

0 votes

1 answer

15

Andrew S. Tanenbaum (OS) Edition 4 Exercise 5 Question 56 (Page No. 434)
Write a program to implement the three disk-arm scheduling algorithms. Write a driver program that generates a sequence of cylinder numbers $(0–999)$ at random, runs the three algorithms for this sequence and prints out the total distance (number of cylinders) the arm needs to traverse in the three algorithms.

admin asked in Operating System Oct 28, 2019

by admin

424 views

0 votes

1 answer

16

Andrew S. Tanenbaum (OS) Edition 4 Exercise 5 Question 32 (Page No. 432)
A slight modification of the elevator algorithm for scheduling disk requests is to always scan in the same direction. In what respect is this modified algorithm better than the elevator algorithm?

admin asked in Operating System Oct 28, 2019

by admin

811 views

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Recent questions tagged disk-scheduling