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A disk drive has 100 cyclinders, numbered 0 to 99. Disk requests come to the disk driver for cyclinders 12, 26, 24, 4, 42, 8 and 50 in that order. The driver is currently serving a request at cyclinder 24. A seek takes 6 msec per cyclinder moved. How much seek time is needed for shortest seek time first (SSTF) algorithm?
- a)0.984 sec
- b)0.396 sec
- c)0.738 sec
- d)0.42 sec
Correct answer is option 'D'. Can you explain this answer?
Verified Answer
A disk drive has 100 cyclinders, numbered 0 to 99. Disk requests come ...
seek time = 2 =(2 + 14 + 4 + 4 + 38 + 8) = 420 msec 1000 msec = 1 sec 420 msec = 0.42 sec So, option (D) is correct.
Most Upvoted Answer
A disk drive has 100 cyclinders, numbered 0 to 99. Disk requests come ...
Given information:
- Disk drive has 100 cylinders, numbered 0 to 99.
- Disk requests come for cylinders 12, 26, 24, 4, 42, 8, and 50.
- The driver is currently serving a request at cylinder 24.
- A seek takes 6 msec per cylinder moved.
Shortest Seek Time First (SSTF) algorithm:
The SSTF algorithm chooses the request that is closest to the current position of the disk head. It minimizes the seek time by selecting the request that requires the shortest distance to be traveled by the disk head.
Calculating the seek time:
To calculate the seek time for the SSTF algorithm, we need to determine the sequence in which the disk requests are serviced. Starting from cylinder 24, we select the request that is closest to the current position and move the disk head accordingly.
1. Initial position: Cylinder 24
2. Select the closest request: Cylinder 26 (distance = 2)
- Seek time: 2 * 6 msec = 12 msec
- New position: Cylinder 26
3. Select the closest request: Cylinder 12 (distance = 14)
- Seek time: 14 * 6 msec = 84 msec
- New position: Cylinder 12
4. Select the closest request: Cylinder 4 (distance = 8)
- Seek time: 8 * 6 msec = 48 msec
- New position: Cylinder 4
5. Select the closest request: Cylinder 8 (distance = 4)
- Seek time: 4 * 6 msec = 24 msec
- New position: Cylinder 8
6. Select the closest request: Cylinder 50 (distance = 42)
- Seek time: 42 * 6 msec = 252 msec
- New position: Cylinder 50
7. Select the closest request: Cylinder 42 (distance = 8)
- Seek time: 8 * 6 msec = 48 msec
- New position: Cylinder 42
8. Select the closest request: Cylinder 24 (distance = 18)
- Seek time: 18 * 6 msec = 108 msec
- New position: Cylinder 24
Total seek time:
The total seek time is the sum of the seek times for each movement:
12 msec + 84 msec + 48 msec + 24 msec + 252 msec + 48 msec + 108 msec = 576 msec
Conversion to seconds:
To convert the seek time to seconds, we divide it by 1000:
576 msec / 1000 = 0.576 sec
Therefore, the seek time needed for the SSTF algorithm is approximately 0.576 seconds.
- Disk drive has 100 cylinders, numbered 0 to 99.
- Disk requests come for cylinders 12, 26, 24, 4, 42, 8, and 50.
- The driver is currently serving a request at cylinder 24.
- A seek takes 6 msec per cylinder moved.
Shortest Seek Time First (SSTF) algorithm:
The SSTF algorithm chooses the request that is closest to the current position of the disk head. It minimizes the seek time by selecting the request that requires the shortest distance to be traveled by the disk head.
Calculating the seek time:
To calculate the seek time for the SSTF algorithm, we need to determine the sequence in which the disk requests are serviced. Starting from cylinder 24, we select the request that is closest to the current position and move the disk head accordingly.
1. Initial position: Cylinder 24
2. Select the closest request: Cylinder 26 (distance = 2)
- Seek time: 2 * 6 msec = 12 msec
- New position: Cylinder 26
3. Select the closest request: Cylinder 12 (distance = 14)
- Seek time: 14 * 6 msec = 84 msec
- New position: Cylinder 12
4. Select the closest request: Cylinder 4 (distance = 8)
- Seek time: 8 * 6 msec = 48 msec
- New position: Cylinder 4
5. Select the closest request: Cylinder 8 (distance = 4)
- Seek time: 4 * 6 msec = 24 msec
- New position: Cylinder 8
6. Select the closest request: Cylinder 50 (distance = 42)
- Seek time: 42 * 6 msec = 252 msec
- New position: Cylinder 50
7. Select the closest request: Cylinder 42 (distance = 8)
- Seek time: 8 * 6 msec = 48 msec
- New position: Cylinder 42
8. Select the closest request: Cylinder 24 (distance = 18)
- Seek time: 18 * 6 msec = 108 msec
- New position: Cylinder 24
Total seek time:
The total seek time is the sum of the seek times for each movement:
12 msec + 84 msec + 48 msec + 24 msec + 252 msec + 48 msec + 108 msec = 576 msec
Conversion to seconds:
To convert the seek time to seconds, we divide it by 1000:
576 msec / 1000 = 0.576 sec
Therefore, the seek time needed for the SSTF algorithm is approximately 0.576 seconds.
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A disk drive has 100 cyclinders, numbered 0 to 99. Disk requests come ...
seek time = 2 =(2 + 14 + 4 + 4 + 38 + 8) = 420 msec 1000 msec = 1 sec 420 msec = 0.42 sec So, option (D) is correct.
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A disk drive has 100 cyclinders, numbered 0 to 99. Disk requests come to the disk driver for cyclinders 12, 26, 24, 4, 42, 8 and 50 in that order. The driver is currently serving a request at cyclinder 24. A seek takes 6 msec per cyclinder moved. How much seek time is needed for shortest seek time first (SSTF) algorithm?a)0.984 secb)0.396 secc)0.738 secd)0.42 secCorrect answer is option 'D'. Can you explain this answer?
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A disk drive has 100 cyclinders, numbered 0 to 99. Disk requests come to the disk driver for cyclinders 12, 26, 24, 4, 42, 8 and 50 in that order. The driver is currently serving a request at cyclinder 24. A seek takes 6 msec per cyclinder moved. How much seek time is needed for shortest seek time first (SSTF) algorithm?a)0.984 secb)0.396 secc)0.738 secd)0.42 secCorrect answer is option '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 A disk drive has 100 cyclinders, numbered 0 to 99. Disk requests come to the disk driver for cyclinders 12, 26, 24, 4, 42, 8 and 50 in that order. The driver is currently serving a request at cyclinder 24. A seek takes 6 msec per cyclinder moved. How much seek time is needed for shortest seek time first (SSTF) algorithm?a)0.984 secb)0.396 secc)0.738 secd)0.42 secCorrect answer is option '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 A disk drive has 100 cyclinders, numbered 0 to 99. Disk requests come to the disk driver for cyclinders 12, 26, 24, 4, 42, 8 and 50 in that order. The driver is currently serving a request at cyclinder 24. A seek takes 6 msec per cyclinder moved. How much seek time is needed for shortest seek time first (SSTF) algorithm?a)0.984 secb)0.396 secc)0.738 secd)0.42 secCorrect answer is option 'D'. Can you explain this answer?.
A disk drive has 100 cyclinders, numbered 0 to 99. Disk requests come to the disk driver for cyclinders 12, 26, 24, 4, 42, 8 and 50 in that order. The driver is currently serving a request at cyclinder 24. A seek takes 6 msec per cyclinder moved. How much seek time is needed for shortest seek time first (SSTF) algorithm?a)0.984 secb)0.396 secc)0.738 secd)0.42 secCorrect answer is option '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 A disk drive has 100 cyclinders, numbered 0 to 99. Disk requests come to the disk driver for cyclinders 12, 26, 24, 4, 42, 8 and 50 in that order. The driver is currently serving a request at cyclinder 24. A seek takes 6 msec per cyclinder moved. How much seek time is needed for shortest seek time first (SSTF) algorithm?a)0.984 secb)0.396 secc)0.738 secd)0.42 secCorrect answer is option '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 A disk drive has 100 cyclinders, numbered 0 to 99. Disk requests come to the disk driver for cyclinders 12, 26, 24, 4, 42, 8 and 50 in that order. The driver is currently serving a request at cyclinder 24. A seek takes 6 msec per cyclinder moved. How much seek time is needed for shortest seek time first (SSTF) algorithm?a)0.984 secb)0.396 secc)0.738 secd)0.42 secCorrect answer is option 'D'. Can you explain this answer?.
Solutions for A disk drive has 100 cyclinders, numbered 0 to 99. Disk requests come to the disk driver for cyclinders 12, 26, 24, 4, 42, 8 and 50 in that order. The driver is currently serving a request at cyclinder 24. A seek takes 6 msec per cyclinder moved. How much seek time is needed for shortest seek time first (SSTF) algorithm?a)0.984 secb)0.396 secc)0.738 secd)0.42 secCorrect answer is option '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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A disk drive has 100 cyclinders, numbered 0 to 99. Disk requests come to the disk driver for cyclinders 12, 26, 24, 4, 42, 8 and 50 in that order. The driver is currently serving a request at cyclinder 24. A seek takes 6 msec per cyclinder moved. How much seek time is needed for shortest seek time first (SSTF) algorithm?a)0.984 secb)0.396 secc)0.738 secd)0.42 secCorrect answer is option 'D'. Can you explain this answer?, a detailed solution for A disk drive has 100 cyclinders, numbered 0 to 99. Disk requests come to the disk driver for cyclinders 12, 26, 24, 4, 42, 8 and 50 in that order. The driver is currently serving a request at cyclinder 24. A seek takes 6 msec per cyclinder moved. How much seek time is needed for shortest seek time first (SSTF) algorithm?a)0.984 secb)0.396 secc)0.738 secd)0.42 secCorrect answer is option 'D'. Can you explain this answer? has been provided alongside types of A disk drive has 100 cyclinders, numbered 0 to 99. Disk requests come to the disk driver for cyclinders 12, 26, 24, 4, 42, 8 and 50 in that order. The driver is currently serving a request at cyclinder 24. A seek takes 6 msec per cyclinder moved. How much seek time is needed for shortest seek time first (SSTF) algorithm?a)0.984 secb)0.396 secc)0.738 secd)0.42 secCorrect answer is option 'D'. Can you explain this answer? theory, EduRev gives you an
ample number of questions to practice A disk drive has 100 cyclinders, numbered 0 to 99. Disk requests come to the disk driver for cyclinders 12, 26, 24, 4, 42, 8 and 50 in that order. The driver is currently serving a request at cyclinder 24. A seek takes 6 msec per cyclinder moved. How much seek time is needed for shortest seek time first (SSTF) algorithm?a)0.984 secb)0.396 secc)0.738 secd)0.42 secCorrect answer is option 'D'. Can you explain this answer? tests, examples and also practice Computer Science Engineering (CSE) tests.
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