GATE CS 1996 Q1.24 — I/O Interface: Interrupt and DMA Mode

In a daisy chain interrupt priority scheme, devices are connected serially to propagate the interrupt acknowledge (INTACK) signal from the processor.

• Priority Distribution: The device physically closest to the processor receives the INTACK signal first. If it has requested an interrupt, it intercepts the signal and blocks it from propagating further. If not, it passes the signal to the next device. Thus, the device closest to the processor has the highest priority, and the device farthest has the lowest priority. This results in non-uniform priority among devices.
• Line Sharing: All devices share a single common interrupt request line (INTR) and a single INTACK line, meaning it does not require a separate interrupt pin on the processor for each device (disproving option D).

Therefore, statement (A) is true.