What signal interrupts the processor and invokes a service routine that…

Concept

A processor can learn about an I/O event either by repeatedly checking device status or through an interrupt. A time-out is an exception event raised when an operation does not finish within a preset interval.

When that event is configured as an interrupt source, control transfers to a service routine, which can diagnose the stalled operation and initiate recovery.

Application

The stem asks for a signal that interrupts the processor specifically so that an error-recovery service routine can run. Among the offered values, Time-out denotes the expiry event associated with a stalled or overlong operation, so it fits that mechanism.

Contrast

• Polling repeatedly reads a device status flag; it is a processor-driven checking method.

• Handshaking uses request and acknowledgement signals to coordinate a transfer between units.

• A strobe is a timing pulse that indicates when data on a bus should be treated as valid.

Cross-check

A time-out condition supplies both features named in the stem: an exceptional event and transfer of control to a recovery routine. The other values describe status checking or transfer coordination.

Therefore, the required signal is Time-out.