Mutex locks in Operating Systems - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the sentence to explain what a mutex lock does.

Operating Systems

A mutex lock is used to [1] access to a shared resource.

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Aallow simultaneous

Bprevent simultaneous

Cignore

Dduplicate

Attempts:

3 left

💡 Hint

Common Mistakes

Thinking mutex allows multiple threads to access at the same time.

Confusing mutex with other synchronization tools.

A mutex lock prevents simultaneous access to a shared resource, ensuring only one thread can use it at a time.

2fill in blank

medium

Complete the sentence to describe what happens when a thread tries to lock a mutex already locked by another thread.

Operating Systems

If a thread tries to lock a mutex that is already locked, it will [1] until the mutex is unlocked.

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Await

Bfail immediately

Cskip the lock

Dlock twice

Attempts:

3 left

💡 Hint

Common Mistakes

Assuming the thread can lock the mutex twice.

Thinking the thread fails immediately without waiting.

The thread will wait (block) until the mutex becomes available to ensure safe access.

3fill in blank

hard

Fix the error in the statement about mutex usage.

Operating Systems

A thread must always [1] a mutex after finishing its work with the shared resource.

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Aignore

Block

Cunlock

Dduplicate

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting to unlock the mutex causing deadlocks.

Trying to lock the mutex again instead of unlocking.

After finishing, a thread must unlock the mutex to allow others to access the resource.

4fill in blank

hard

Fill both blanks to complete the explanation of mutex behavior.

Operating Systems

When a mutex is [1], other threads trying to [2] it will be blocked.

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Alocked

Bignore

Clock

Dunlock

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing locking and unlocking states.

Assuming threads ignore the mutex state.

When a mutex is locked, other threads trying to lock it will be blocked until it is unlocked.

5fill in blank

hard

Fill all three blanks to complete the dictionary comprehension that maps thread IDs to their lock status if the mutex is locked.

Operating Systems

status = { [1]: [2] for [3] in threads if mutex.is_locked() }

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Athread_id

Blocked

Attempts:

3 left

💡 Hint

Common Mistakes

Using the same variable for key and value incorrectly.

Not checking if the mutex is locked before creating the dictionary.

This comprehension creates a dictionary with thread IDs as keys and their lock status as values when the mutex is locked.