The PDP-11 was one of the first systems to use vectorized interrupts and interrupt chaining. This meant that when an interrupt occurred, the CPU could jump directly to a specific handler for that device, execute its code, and even pass control to other handlers if needed. Once completed, execution would resume exactly where it left off.

For example, a sensor connected via a bus card could trigger an interrupt when new data was available, allowing code to store the value in memory or write it to disk automatically, without the main program needing to check for updates. This eliminated the need for wasteful polling, making the system more efficient and responsive by handling events asynchronously in the background.