B. From the processor point of view; the action for an input is as follows: :

• The processor issues a READ command.
  
• It then does something else
  (e.g. the processor may be working on several different programs at the same time)
  
• At the end of each instruction cycle, the processor checks for interrupts
  
• When the interrupt from an I/O module occurs, the processor saves the context
  (e.g. program counter & processor registers) of the current program and processes the interrupt.
  
• In this case, the processor reads the word of data from the I/O module and stores it in memory.
  
• It then restores the context of the program it was working on and resumes execution.