Final answer:
Parallelism involves the simultaneous execution of tasks on hardware with multiple processors, whereas concurrency involves managing multiple tasks and providing the illusion of parallel execution through scheduling. Both have unique challenges like resource contention in parallelism and synchronization issues in concurrency.
Step-by-step explanation:
Parallelism and concurrency are two distinct but related concepts within the sphere of operating systems with unique challenges. Parallelism deals with the execution of multiple tasks simultaneously. This can be achieved on a computer with multiple CPUs (Central Processing Units) or a single CPU with multiple cores. The main challenge is to optimize the use of hardware resources so that tasks are executed in parallel without interference or contention for these resources.
On the other hand, concurrency is about dealing with lots of tasks at once and having the system switch between these tasks rapidly, thus giving the illusion of simultaneous execution. Concurrency's primary challenge lies in the synchronization and coordination of access to shared resources without causing deadlock or resource starvation. Concurrency requires careful task scheduling and management by the operating system to maximize efficiency.
In conclusion, while parallelism and concurrency both aim to optimize task execution, they present different challenges in how an operating system manages, executes, and coordinates tasks on computing hardware.