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Consider a disk system with 100 cylinders. The requests to access the cylinders occur in the following sequence:
16, 24, 7, 9, 25, 11, 8, 87
Assuming that the head is currently at cylinder 58, what is the time taken (in ms) to satisfy all requests if first come first serve policy is used?
    Correct answer is '181'. Can you explain this answer?
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    Consider a disk system with 100 cylinders. The requests to access the ...
    (58 – 16) + (24 - 16) + (24 - 7) + (9 - 7) + (25 - 9) + (25 - 11) + (11 - 8) + (87 - 8)
    = 42 + 8 + 17 + 2 + 16 + 14 + 3 + 79
    = 181 ms
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    Consider a disk system with 100 cylinders. The requests to access the ...
    First Come First Serve (FCFS) Disk Scheduling Algorithm

    The First Come First Serve (FCFS) disk scheduling algorithm is a simple disk scheduling algorithm where the requests are executed in the order they arrive. In this algorithm, the head moves from its current position to the first request cylinder and then processes the subsequent requests in the order they were received.

    Given Information:
    - Total number of cylinders: 100
    - Cylinder requests sequence: 16, 24, 7, 9, 25, 11, 8, 87
    - Current position of the head: 58

    Steps to Calculate the Time Taken:

    1. Calculate the total distance the head needs to travel:
    - Start with the current head position (58).
    - Calculate the absolute difference between the current head position and the first request cylinder (16). Add this value to the total distance.
    - Update the current head position to the first request cylinder (16).
    - Repeat the above steps for all subsequent request cylinders, adding the absolute difference to the total distance.
    - The final total distance is the sum of all absolute differences.

    2. Calculate the time taken based on the total distance:
    - As per the question, each cylinder access takes 1 ms.
    - Multiply the total distance by the time taken per cylinder access (1 ms) to get the total time taken.

    Calculating the Total Distance:

    - Absolute difference between 58 and 16: |58 - 16| = 42
    - Absolute difference between 16 and 24: |16 - 24| = 8
    - Absolute difference between 24 and 7: |24 - 7| = 17
    - Absolute difference between 7 and 9: |7 - 9| = 2
    - Absolute difference between 9 and 25: |9 - 25| = 16
    - Absolute difference between 25 and 11: |25 - 11| = 14
    - Absolute difference between 11 and 8: |11 - 8| = 3
    - Absolute difference between 8 and 87: |8 - 87| = 79

    Total distance = 42 + 8 + 17 + 2 + 16 + 14 + 3 + 79 = 181

    Calculating the Time Taken:

    Total time taken = Total distance * Time taken per cylinder access
    = 181 * 1 ms
    = 181 ms

    Therefore, the time taken to satisfy all the requests using the First Come First Serve (FCFS) disk scheduling algorithm is 181 ms.
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    Consider a storage disk with 4 platters (numbered as 0, 1, 2 and 3), 200 cylinders (numbered as 0, 1, … , 199), and 256 sectors per track (numbered as 0, 1, … , 255). The following 6 disk requests of the form [sector number, cylinder number, platter number] are received by the disk controller at the same time: [120, 72, 2] , [180, 134, 1] , [60, 20, 0] , [212, 86, 3] , [56, 116, 2] , [118, 16, 1] Currently the head is positioned at sector number 100 of cylinder 80, and is moving towards higher cylinder numbers. The average power dissipation in moving the head over 100 cylinders is 20 milliwatts and for reversing the direction of the head movement once is 15 milliwatts. Power dissipation associated with rotational latency and switching of head between different platters is negligible. The total power consumption in milliwatts to satisfy all of the above disk requests using the Shortest Seek Time First disk scheduling algorithm is _______. Correct answer is '85'. Can you explain this answer?

    Consider a storage disk with 4 platters (numbered as 0, 1, 2 and 3), 200 cylinders (numbered as 0, 1, … , 199), and 256 sectors per track (numbered as 0, 1, … 255). The following 6 disk requests of the form [sector number, cylinder number, platter number] are received by the disk controller at the same time: [120, 72, 2], [180, 134, 1], [60, 20, 0], [212, 86, 3], [56, 116, 2], [118, 16, 1] Currently head is positioned at sector number 100 of cylinder 80, and is moving towards higher cylinder numbers. The average power dissipation in moving the head over 100 cylinders is 20 milliwatts and for reversing the direction of the head movement once is 15 milliwatts. Power dissipation associated with rotational latency and switching of head between different platters is negligible. The total power consumption in milliwatts to satisfy all of the above disk requests using the Shortest Seek Time First disk scheduling algorithm is ______ .Note -This was Numerical Type question.

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    Consider a disk system with 100 cylinders. The requests to access the cylinders occur in the following sequence:16, 24, 7, 9, 25, 11, 8, 87Assuming that the head is currently at cylinder 58, what is the time taken (in ms) to satisfy all requests if first come first serve policy is used?Correct answer is '181'. Can you explain this answer?
    Question Description
    Consider a disk system with 100 cylinders. The requests to access the cylinders occur in the following sequence:16, 24, 7, 9, 25, 11, 8, 87Assuming that the head is currently at cylinder 58, what is the time taken (in ms) to satisfy all requests if first come first serve policy is used?Correct answer is '181'. Can you explain this answer? for Computer Science Engineering (CSE) 2024 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 Consider a disk system with 100 cylinders. The requests to access the cylinders occur in the following sequence:16, 24, 7, 9, 25, 11, 8, 87Assuming that the head is currently at cylinder 58, what is the time taken (in ms) to satisfy all requests if first come first serve policy is used?Correct answer is '181'. Can you explain this answer? covers all topics & solutions for Computer Science Engineering (CSE) 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Consider a disk system with 100 cylinders. The requests to access the cylinders occur in the following sequence:16, 24, 7, 9, 25, 11, 8, 87Assuming that the head is currently at cylinder 58, what is the time taken (in ms) to satisfy all requests if first come first serve policy is used?Correct answer is '181'. Can you explain this answer?.
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