Classification of interrupts: 

1. a) asynchronous

•   external components or hardware malfunction

1.b)synchronous

•   function of program state (for example overflow, page fault)

2a. coerced

•   from OS or hardware (protection violation ,page fault)

2b. user request

•   OS call

3a. Non-Maskable

User cannot disable processing

3b. User Maskable

User can disable processing

4a. within an instruction

Usually synchronous - Harder to deal with

4b. between Instructions

Usually asynchronous

5a. Termination

5b. Resume

•   As if nothing is happened? Program will continue to execution