Languages-Assembly Language [3i Infotech Placement]: Sample Questions 33 - 34 of 51

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Question 33

Assembly Language

Describe in Detail


What method is used in Win in multitasking?


  • Windows had non-pre-emptive scheduling till Windows , after which it changed to pre-emptive from Windows .
  • In non-pre-emptive scheduling, a task runs until it stops (voluntarily) , or finishes.
    • The Scheduler then checks all tasks՚ states and schedules the next highest priority task in ready state.
    • In non-pre-emptive scheduling a task assigned to the CPU, cannot be taken away, even if short tasks have to wait.
    • In non-pre-emptive scheduling each task gets its՚ share of the CPU, avoiding delay in the task.
    • The ‘amount of time’ allocated to the CPU may not necessarily be equal, as it depends on how long the task takes to complete.
  • In pre-emptive scheduling, a task waiting for other resources is pre-emptively put to wait state and other ready task is scheduled.

Question 34

Assembly Language



What action is taken when the processor under execution is interrupted by a non-maskable interrupt?


Choice (4)


Processor serves the interrupt request after completing the execution of the current instruction.


Processor serving the interrupt request depends upon the priority of the current task under execution.


Processor serves the interupt request immediately.


Processor serves the interupt request after completing the current task.




Non- maskable interrupt pin has higher priority than the maskable interrupt request pin.

On a non-maskable interrupt (NMI)

On an NMI, these actions take place:

  • Completes the current instruction.
  • Pushes the Flag register, CS and IP return address on the stack.
  • IP is loaded from word location H and CS is loaded from next word location AH.
  • Interrupt flag and trap flag are reset to
  • The processor then starts executing the NMI service routine.

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