Deadlock avoidance (Banker's algorithm) in Operating Systems - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare the maximum resource matrix in Banker's algorithm.

Operating Systems

max_resources = [[7, 5, 3], [3, 2, [1]], [9, 0, 2]]

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

A5

B4

C2

D3

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing allocated resources with maximum demand.

Using a value not consistent with the matrix pattern.

The maximum resource matrix defines the maximum demand of each process. Here, the missing value is 2 to match the example matrix.

2fill in blank

medium

Complete the code to calculate the Need matrix in Banker's algorithm.

Operating Systems

need = [[max_resources[i][j] - [1][i][j] for j in range(m)] for i in range(n)]

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Arequest

Ballocation

Cavailable

Dmax_resources

Attempts:

3 left

💡 Hint

Common Mistakes

Subtracting available resources instead of allocated.

Using the wrong matrix for calculation.

The Need matrix is calculated by subtracting the allocated resources from the maximum resources for each process.

3fill in blank

hard

Fix the error in the safety check condition to verify if a process can be safely allocated resources.

Operating Systems

if all(need[i][j] <= [1][j] for j in range(m)):

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Aallocation

Brequest

Cmax_resources

Davailable

Attempts:

3 left

💡 Hint

Common Mistakes

Comparing Need with Allocation or Max resources.

Using the request matrix incorrectly.

The safety check compares the Need matrix with the Available resources to decide if the process can proceed safely.

4fill in blank

hard

Fill both blanks to update the Available resources and Allocation matrix after granting a request.

Operating Systems

available = [available[j] - [1][j] for j in range(m)]
allocation[process_id] = [allocation[process_id][j] + [2][j] for j in range(m)]

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Arequest

Ballocation

Cavailable

Dneed

Attempts:

3 left

💡 Hint

Common Mistakes

Using Allocation or Need instead of Request for updates.

Updating Available incorrectly.

When a request is granted, Available resources decrease by the request amount, and Allocation for the process increases by the same request.

5fill in blank

hard

Fill all three blanks to check if the system is in a safe state after resource allocation.

Operating Systems

finish = [False] * n
work = available.copy()
for i in range(n):
    if not finish[i] and all(need[i][j] <= [1][j] for j in range(m)):
        work = [work[j] + [2][i][j] for j in range(m)]
        finish[i] = [3]

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Awork

Ballocation

CTrue

DFalse

Attempts:

3 left

💡 Hint

Common Mistakes

Using Available instead of Work in the condition.

Marking finish as False instead of True.

Updating Work incorrectly.

The safety algorithm checks if Need is less than or equal to Work (initially Available). If yes, it adds Allocation of that process to Work and marks the process as finished (True).