Peterson's solution in Operating Systems - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare the flag array used in Peterson's solution.

Operating Systems

boolean flag[2] = { [1], [1] };

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

Afalse

Btrue

Cnull

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Setting flags to true initially, which incorrectly indicates both processes want to enter.

Using 0 or null instead of boolean false.

The flag array is initialized to false for both processes, indicating neither wants to enter the critical section initially.

2fill in blank

medium

Complete the code to assign the turn variable in Peterson's solution.

Operating Systems

turn = [1];

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A0

Bother

C1

Dprocess_id

Attempts:

3 left

💡 Hint

Common Mistakes

Setting turn to the current process's ID instead of the other process.

Using fixed values like 0 or 1 without considering the other process.

The turn variable is assigned the other process's ID to give it priority in entering the critical section.

3fill in blank

hard

Fix the error in the waiting condition of Peterson's solution.

Operating Systems

while (flag[[1]] && turn == [1]) { /* wait */ }

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

Ai

B1

C0

Dj

Attempts:

3 left

💡 Hint

Common Mistakes

Using the current process's index instead of the other process's index.

Confusing the turn variable with the flag array index.

The waiting condition checks if the other process (j) wants to enter and if it's that process's turn.

4fill in blank

hard

Fill both blanks to correctly set flags and turn in Peterson's solution for process i.

Operating Systems

flag[[1]] = true;
turn = [2];

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

Ai

Bj

C0

D1

Attempts:

3 left

💡 Hint

Common Mistakes

Setting turn to the same process's ID.

Setting the wrong flag index.

Process i sets its flag to true indicating it wants to enter, and sets turn to j to give priority to the other process.

5fill in blank

hard

Fill all three blanks to complete the exit section of Peterson's solution for process i.

Operating Systems

flag[[1]] = [2];
// Process [3] exits critical section

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

Ai

Bfalse

Dtrue

Attempts:

3 left

💡 Hint

Common Mistakes

Setting flag to true instead of false on exit.

Using the wrong process ID in the comment.

Process i sets its flag to false to indicate it no longer wants to enter the critical section and exits.