Interrupt handling strategies in computer systems An interrupt method that requires the CPU to test each peripheral device in sequence to determine the source is called ________.

Introduction / Context:
Computers interface with multiple peripherals that may request service. How the CPU discovers which device raised an interrupt significantly affects latency and software complexity. Two common schemes are polled and vectored interrupts.

Given Data / Assumptions:

• Multiple devices can signal a need for service.
• The CPU must identify the requesting device before running its service routine.
• In the described method, the CPU checks devices one by one.

Concept / Approach:
In polled I/O, the CPU executes a polling loop that queries each device’s status register in a fixed order. The first device reporting a pending request is then serviced. In contrast, vectored interrupts provide a hardware-supplied vector that directly identifies the device and entry point for the service routine.

Step-by-Step Solution:

Verification / Alternative check:
Any architecture reference that describes polled interrupt service shows a loop over device flags; vectored service avoids this by using a hardware-provided address.

Why Other Options Are Wrong:
“vectored I/O” provides an immediate vector, no sequential testing. “programmed interrupt” is not a standard term for this behavior. “interrupt-driven I/O” is generic and can be vectored or polled.

Common Pitfalls:
High interrupt latency when many devices are polled; missing priority handling; forgetting to clear the source flag causing repeated servicing.

Final Answer:
polled I/O