Asynchronous programming is a concurrency model, alternative to OS-managed threads, in which execution units suspend at well-defined await points while waiting on I/O rather than being preemptively scheduled, allowing many pending operations to be in flight on a single thread without the shared-memory race conditions or scheduling overhead inherent to multithreading. The model is built on the future/promise abstraction (a placeholder for a value not yet computed, formalized in academic work since the 1970s), and in Python is realized through the `async`/`await` syntax, where `async` marks a coroutine function and `await` suspends execution until an awaited coroutine resolves. This belongs to the broader discipline of concurrent and parallel computing, contrasting cooperative, single-threaded concurrency (asyncio) against preemptive, multi-threaded/multi-process concurrency (OS threads and processes).
Asynchronous programming is a concurrency model, alternative to OS-managed threads, in which execution units suspend at well-defined await points while waiting on I/O rather than being preemptively s…