Final answer:
The difference between asynchronous IO and signal driven IO is that asynchronous IO allows the application to execute IO operations without waiting for them to complete and be notified upon completion, while signal driven IO signals the application when the IO operation can be performed non-blocking.
Step-by-step explanation:
Difference Between Asynchronous IO and Signal Driven IO
The main difference between asynchronous IO and signal driven IO lies in the way an application is alerted to the availability of IO operations. In asynchronous IO, the application executes an IO operation and then proceeds with other tasks without waiting for the IO operation to complete. The system notifies the application when the IO operation is finished, allowing it to process the data. This model improves performance by not blocking the application during the IO operation. Examples of asynchronous IO include POSIX AIO and Windows Overlapped IO.
On the other hand, signal driven IO is a mechanism where the application instructs the operating system to signal it (using UNIX signals, for example) when a particular IO operation can be performed without blocking. The application is then responsible for initiating the IO operation itself upon receiving the signal. This model allows the application to be aware of when it can perform non-blocking IO operation without continuously polling the IO resource.
Both mechanisms serve to improve the efficiency of IO operations by reducing the need for busy-waiting and allowing applications to handle other tasks concurrently. However, the primary difference lies in how and when an application is notified of IO readiness and takes action accordingly.