Concurrency considerations in LLD - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is concurrency in system design?

Concurrency means multiple tasks or processes are happening at the same time or overlapping in time to improve efficiency and performance.

beginner

Why do we need locks or mutexes in concurrent systems?

Locks or mutexes prevent multiple processes from changing the same data at the same time, avoiding errors and data corruption.

intermediate

What is a race condition?

A race condition happens when two or more processes try to change shared data at the same time, causing unpredictable results.

intermediate

Explain deadlock in concurrency.

Deadlock is when two or more processes wait forever for each other to release resources, so none can continue.

intermediate

What is the difference between concurrency and parallelism?

Concurrency is about managing multiple tasks at once, possibly by switching between them. Parallelism is running multiple tasks exactly at the same time using multiple processors.

What problem does a mutex solve in concurrent systems?

A Automatically fixes bugs in code

B Increases the speed of a single process

C Allows unlimited access to shared resources

D Prevents multiple processes from accessing shared data simultaneously

Mutexes ensure only one process accesses shared data at a time to avoid conflicts.

Which of the following best describes a race condition?

A Processes waiting forever for each other

B Multiple processes accessing shared data causing unpredictable results

C A process running faster than expected

D A system crash due to hardware failure

Race conditions occur when concurrent processes access shared data without proper synchronization.

Deadlock occurs when:

A A single process crashes

B Processes run in parallel without issues

C Processes wait forever for resources held by each other

D Resources are never requested

Deadlock is a state where processes wait endlessly for resources locked by each other.

Which technique helps avoid race conditions?

A Using locks or synchronization mechanisms

B Running processes sequentially only

C Ignoring shared data

D Increasing CPU speed

Locks and synchronization ensure safe access to shared data, preventing race conditions.

What is the main difference between concurrency and parallelism?

A Concurrency is multitasking; parallelism is multitasking on multiple processors

B Concurrency is faster than parallelism

C Parallelism uses one processor only

D They are the same

Concurrency manages multiple tasks by switching; parallelism runs tasks simultaneously on multiple processors.

Describe common concurrency problems and how to handle them.

Think about what happens when multiple processes share data or resources.

Explain the difference between concurrency and parallelism with examples.

Consider how tasks are managed or executed at the same time.