Which method does an OS use for interrupt handling by checking each device for requests?

The method used by an operating system for interrupt handling that involves checking each device for requests is polling. In polling, the OS actively queries each device in a systematic manner to determine whether it needs attention or has an interrupt to process. This method involves the CPU repeatedly checking the status of devices in a loop, which can lead to inefficiencies and increased CPU utilization, especially if devices are infrequently requesting service.

Polling is typically employed in systems where fast response times are not critical, or when the number of devices is manageable. This contrasts with techniques like interrupt-driven I/O, where devices signal the CPU only when they need service, allowing for more efficient handling of requests as the CPU can dedicate its time to executing other processes when no interrupts are occurring.

In summary, polling effectively manages device requests by actively checking each one, which allows the OS to stay informed about the current status of devices and respond appropriately to their needs.