ITPEC FE Morning October 2020 Question 11

External vs Internal Interrupts — identify the source of an interrupt signal.

External interrupt — triggered by a signal from an outside device (timer, I/O controller, keyboard).

Internal interrupt — generated by the CPU itself during instruction execution (exceptions, traps).

• •(a) Timer notification — timer is an external hardware device → external interrupt ✓
• •(b) Division by zero — CPU detects arithmetic error during execution → internal
• •(c) Non-existent operation code — CPU encounters invalid opcode → internal
• •(d) Page fault — CPU's memory unit detects missing page → internal

Key rule: If the signal comes from outside the CPU → external. If the CPU generates it while executing an instruction → internal.

AI-generated — may contain errors