Explain Concurrency in Computer Systems

Q: Explain concurrency in computer systems. A: Concurrency is the ability of a system to make progress on multiple tasks during overlapping time periods, which may involve true parallelism (multiple CPU cores executing simultaneously) or interleaved execution on a single core via context switching. Key concepts: threads/processes, race conditions (when shared state is accessed without synchronization), critical sections, and synchronization primitives (mutexes, semaphores, monitors) that prevent race conditions at the cost of possible contention/deadlock. Contrast concurrency (dealing with many things at once, structurally) with parallelism (doing many things at once, literally, requiring multiple cores). Be ready to discuss deadlock, starvation, and livelock, and how modern languages (Go's goroutines/channels, Java's ExecutorService) model concurrency.