FCFS disk scheduling in Operating Systems - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to calculate the total head movement in FCFS disk scheduling.

Operating Systems

total_movement = 0
for i in range(1, len(requests)):
    total_movement += abs(requests[i] [1] requests[i-1])

Drag options to blanks, or click blank then click option'

A/

B*

C+

D-

Attempts:

3 left

💡 Hint

Common Mistakes

Using addition instead of subtraction inside the absolute value.

Forgetting to use absolute value, which can cause negative distances.

In FCFS disk scheduling, the total head movement is the sum of absolute differences between consecutive requests. We subtract the previous request from the current to find the distance moved.

2fill in blank

medium

Complete the code to initialize the starting position of the disk head.

Operating Systems

head_position = [1]

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Arequests[0]

B-1

C0

Dlen(requests)

Attempts:

3 left

💡 Hint

Common Mistakes

Setting head position to 0 regardless of requests.

Using the length of requests instead of a position.

The disk head starts at the first request in the queue in FCFS scheduling.

3fill in blank

hard

Fix the error in the loop that calculates head movement for FCFS scheduling.

Operating Systems

for i in range(1, len(requests)):
    movement = abs(requests[i] [1] requests[i-1])
    total_movement += movement

Drag options to blanks, or click blank then click option'

A*

B+

C-

D/

Attempts:

3 left

💡 Hint

Common Mistakes

Using the same index for both current and previous requests.

Using addition instead of subtraction.

The loop should subtract the previous request (requests[i-1]) from the current (requests[i]) to get the movement. Using requests[i] twice is incorrect.

4fill in blank

hard

Fill both blanks to create a dictionary that maps each request to its head movement from the previous request.

Operating Systems

movements = {req: abs(req [1] prev) for req, prev in zip(requests[1:], requests[2])}

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A-

B+

C[:-1]

D[1:]

Attempts:

3 left

💡 Hint

Common Mistakes

Using addition instead of subtraction.

Using the wrong slice for previous requests.

The dictionary comprehension calculates the absolute difference between each request and the previous one. The previous requests are requests[:-1].

5fill in blank

hard

Fill all three blanks to compute total head movement and print the result in FCFS disk scheduling.

Operating Systems

total_movement = 0
for i in range(1, [1]):
    total_movement += abs(requests[i] [2] requests[i-1])
print(f"Total head movement: [3]")

Drag options to blanks, or click blank then click option'

Alen(requests)

B-

Ctotal_movement

Drequests

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong range limit in the loop.

Printing the wrong variable.

The loop runs from 1 to the length of requests. The movement is the absolute difference between current and previous requests. Finally, total_movement is printed.