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Disk requests come to a disk driver for cylinders in the order 11, 23, 21, 3, 41, x, 25, and 39, at a time when the disk drive is reading from cylinder 15. The seek time is 4 ms/cylinder. The total seek time, if the disk arm scheduling algorithm is first-come-first-served is 560 ms. What is/are the value of x?
- a)The value of x is 118.
- b)The value of x is 0.
- c)The value of x is 59.
- d)The value of x is 7.
Correct answer is option 'C,D'. Can you explain this answer?
Most Upvoted Answer
Disk requests come to a disk driver for cylinders in the order 11, 23,...
Total Seek Time Calculation
To calculate the total seek time using the first-come-first-serve disk arm scheduling algorithm, we need to determine the number of cylinders the disk arm needs to move for each disk request.
Given:
Current cylinder: 15
Disk requests: 11, 23, 21, 3, 41, x, 25, 39
We can calculate the seek time for each disk request by subtracting the current cylinder from the requested cylinder and multiplying it by the seek time per cylinder (4 ms/cylinder).
Seek Time Calculation for each Disk Request
1. Seek time for cylinder 11: (11 - 15) * 4 = -4 * 4 = -16 ms (The disk arm doesn't need to move backward, so the seek time is 0 ms.)
2. Seek time for cylinder 23: (23 - 15) * 4 = 8 * 4 = 32 ms
3. Seek time for cylinder 21: (21 - 15) * 4 = 6 * 4 = 24 ms
4. Seek time for cylinder 3: (3 - 15) * 4 = -12 * 4 = -48 ms (The disk arm doesn't need to move backward, so the seek time is 0 ms.)
5. Seek time for cylinder 41: (41 - 15) * 4 = 26 * 4 = 104 ms
6. Seek time for cylinder x: (x - 15) * 4 = x * 4 - 60 ms (We don't know the value of x yet, so let's keep it as x for now.)
7. Seek time for cylinder 25: (25 - 15) * 4 = 10 * 4 = 40 ms
8. Seek time for cylinder 39: (39 - 15) * 4 = 24 * 4 = 96 ms
Total Seek Time Calculation
The total seek time is the sum of the seek times for all the disk requests.
Total Seek Time = 0 + 32 + 24 + 0 + 104 + x * 4 - 60 + 40 + 96 = 560 ms
Simplifying the equation:
x * 4 + 136 = 560
x * 4 = 560 - 136
x * 4 = 424
x = 424 / 4
x = 106
Therefore, the value of x is 106.
However, none of the given options matches the calculated value of x. It seems there might be an error in the options or the given information. It is not possible to determine the correct value of x based on the provided options.
To calculate the total seek time using the first-come-first-serve disk arm scheduling algorithm, we need to determine the number of cylinders the disk arm needs to move for each disk request.
Given:
Current cylinder: 15
Disk requests: 11, 23, 21, 3, 41, x, 25, 39
We can calculate the seek time for each disk request by subtracting the current cylinder from the requested cylinder and multiplying it by the seek time per cylinder (4 ms/cylinder).
Seek Time Calculation for each Disk Request
1. Seek time for cylinder 11: (11 - 15) * 4 = -4 * 4 = -16 ms (The disk arm doesn't need to move backward, so the seek time is 0 ms.)
2. Seek time for cylinder 23: (23 - 15) * 4 = 8 * 4 = 32 ms
3. Seek time for cylinder 21: (21 - 15) * 4 = 6 * 4 = 24 ms
4. Seek time for cylinder 3: (3 - 15) * 4 = -12 * 4 = -48 ms (The disk arm doesn't need to move backward, so the seek time is 0 ms.)
5. Seek time for cylinder 41: (41 - 15) * 4 = 26 * 4 = 104 ms
6. Seek time for cylinder x: (x - 15) * 4 = x * 4 - 60 ms (We don't know the value of x yet, so let's keep it as x for now.)
7. Seek time for cylinder 25: (25 - 15) * 4 = 10 * 4 = 40 ms
8. Seek time for cylinder 39: (39 - 15) * 4 = 24 * 4 = 96 ms
Total Seek Time Calculation
The total seek time is the sum of the seek times for all the disk requests.
Total Seek Time = 0 + 32 + 24 + 0 + 104 + x * 4 - 60 + 40 + 96 = 560 ms
Simplifying the equation:
x * 4 + 136 = 560
x * 4 = 560 - 136
x * 4 = 424
x = 424 / 4
x = 106
Therefore, the value of x is 106.
However, none of the given options matches the calculated value of x. It seems there might be an error in the options or the given information. It is not possible to determine the correct value of x based on the provided options.
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Community Answer
Disk requests come to a disk driver for cylinders in the order 11, 23,...
Given,
Seek time = t = 4 ms/cylinder.
Head = 15
Now,
Since it is a first-come-first-serve scheduling request will be served in the given sequence:
11, 23, 21, 3, 41, x, 25 and 39.
Diagram:
As we know,
Total seek time = Total head movement x t
Now,
560 = total head movement x 4
Total head movement = 140
⇒ (15 − 11) + (23 − 11) + (23 − 21) + (21 − 3) + (41 − 3) + |41 − x| + |25 − x| + (39 − 25) = 140
⇒ 4 + 12 + 2 + 18 + 38 + |41 − x| + |25 − x| + 14 = 140
⇒ 88 + |41 − x| + |25 − x| = 140
⇒ |41 − x| + |25 − x| = 52
Case 1:
⇒ 66 − 2x = 52
∴ x = 7
Case 2:
⇒ 2x − 66 = 52
∴ x = 59
Hence, the correct options are (C) and (D).
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Disk requests come to a disk driver for cylinders in the order 11, 23, 21, 3, 41, x, 25, and 39, at a time when the disk drive is reading from cylinder 15. The seek time is 4 ms/cylinder. The total seek time, if the disk arm scheduling algorithm is first-come-first-served is 560 ms. What is/are the value of x?a)The value of x is 118.b)The value of x is 0.c)The value of x is 59.d)The value of x is 7.Correct answer is option 'C,D'. Can you explain this answer?
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Disk requests come to a disk driver for cylinders in the order 11, 23, 21, 3, 41, x, 25, and 39, at a time when the disk drive is reading from cylinder 15. The seek time is 4 ms/cylinder. The total seek time, if the disk arm scheduling algorithm is first-come-first-served is 560 ms. What is/are the value of x?a)The value of x is 118.b)The value of x is 0.c)The value of x is 59.d)The value of x is 7.Correct answer is option 'C,D'. Can you explain this answer? for Computer Science Engineering (CSE) 2025 is part of Computer Science Engineering (CSE) preparation. The Question and answers have been prepared according to the Computer Science Engineering (CSE) exam syllabus. Information about Disk requests come to a disk driver for cylinders in the order 11, 23, 21, 3, 41, x, 25, and 39, at a time when the disk drive is reading from cylinder 15. The seek time is 4 ms/cylinder. The total seek time, if the disk arm scheduling algorithm is first-come-first-served is 560 ms. What is/are the value of x?a)The value of x is 118.b)The value of x is 0.c)The value of x is 59.d)The value of x is 7.Correct answer is option 'C,D'. Can you explain this answer? covers all topics & solutions for Computer Science Engineering (CSE) 2025 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Disk requests come to a disk driver for cylinders in the order 11, 23, 21, 3, 41, x, 25, and 39, at a time when the disk drive is reading from cylinder 15. The seek time is 4 ms/cylinder. The total seek time, if the disk arm scheduling algorithm is first-come-first-served is 560 ms. What is/are the value of x?a)The value of x is 118.b)The value of x is 0.c)The value of x is 59.d)The value of x is 7.Correct answer is option 'C,D'. Can you explain this answer?.
Disk requests come to a disk driver for cylinders in the order 11, 23, 21, 3, 41, x, 25, and 39, at a time when the disk drive is reading from cylinder 15. The seek time is 4 ms/cylinder. The total seek time, if the disk arm scheduling algorithm is first-come-first-served is 560 ms. What is/are the value of x?a)The value of x is 118.b)The value of x is 0.c)The value of x is 59.d)The value of x is 7.Correct answer is option 'C,D'. Can you explain this answer? for Computer Science Engineering (CSE) 2025 is part of Computer Science Engineering (CSE) preparation. The Question and answers have been prepared according to the Computer Science Engineering (CSE) exam syllabus. Information about Disk requests come to a disk driver for cylinders in the order 11, 23, 21, 3, 41, x, 25, and 39, at a time when the disk drive is reading from cylinder 15. The seek time is 4 ms/cylinder. The total seek time, if the disk arm scheduling algorithm is first-come-first-served is 560 ms. What is/are the value of x?a)The value of x is 118.b)The value of x is 0.c)The value of x is 59.d)The value of x is 7.Correct answer is option 'C,D'. Can you explain this answer? covers all topics & solutions for Computer Science Engineering (CSE) 2025 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Disk requests come to a disk driver for cylinders in the order 11, 23, 21, 3, 41, x, 25, and 39, at a time when the disk drive is reading from cylinder 15. The seek time is 4 ms/cylinder. The total seek time, if the disk arm scheduling algorithm is first-come-first-served is 560 ms. What is/are the value of x?a)The value of x is 118.b)The value of x is 0.c)The value of x is 59.d)The value of x is 7.Correct answer is option 'C,D'. Can you explain this answer?.
Solutions for Disk requests come to a disk driver for cylinders in the order 11, 23, 21, 3, 41, x, 25, and 39, at a time when the disk drive is reading from cylinder 15. The seek time is 4 ms/cylinder. The total seek time, if the disk arm scheduling algorithm is first-come-first-served is 560 ms. What is/are the value of x?a)The value of x is 118.b)The value of x is 0.c)The value of x is 59.d)The value of x is 7.Correct answer is option 'C,D'. Can you explain this answer? in English & in Hindi are available as part of our courses for Computer Science Engineering (CSE).
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Disk requests come to a disk driver for cylinders in the order 11, 23, 21, 3, 41, x, 25, and 39, at a time when the disk drive is reading from cylinder 15. The seek time is 4 ms/cylinder. The total seek time, if the disk arm scheduling algorithm is first-come-first-served is 560 ms. What is/are the value of x?a)The value of x is 118.b)The value of x is 0.c)The value of x is 59.d)The value of x is 7.Correct answer is option 'C,D'. Can you explain this answer?, a detailed solution for Disk requests come to a disk driver for cylinders in the order 11, 23, 21, 3, 41, x, 25, and 39, at a time when the disk drive is reading from cylinder 15. The seek time is 4 ms/cylinder. The total seek time, if the disk arm scheduling algorithm is first-come-first-served is 560 ms. What is/are the value of x?a)The value of x is 118.b)The value of x is 0.c)The value of x is 59.d)The value of x is 7.Correct answer is option 'C,D'. Can you explain this answer? has been provided alongside types of Disk requests come to a disk driver for cylinders in the order 11, 23, 21, 3, 41, x, 25, and 39, at a time when the disk drive is reading from cylinder 15. The seek time is 4 ms/cylinder. The total seek time, if the disk arm scheduling algorithm is first-come-first-served is 560 ms. What is/are the value of x?a)The value of x is 118.b)The value of x is 0.c)The value of x is 59.d)The value of x is 7.Correct answer is option 'C,D'. Can you explain this answer? theory, EduRev gives you an
ample number of questions to practice Disk requests come to a disk driver for cylinders in the order 11, 23, 21, 3, 41, x, 25, and 39, at a time when the disk drive is reading from cylinder 15. The seek time is 4 ms/cylinder. The total seek time, if the disk arm scheduling algorithm is first-come-first-served is 560 ms. What is/are the value of x?a)The value of x is 118.b)The value of x is 0.c)The value of x is 59.d)The value of x is 7.Correct answer is option 'C,D'. Can you explain this answer? tests, examples and also practice Computer Science Engineering (CSE) tests.
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