Midterm - Quiz 4

15 Questions | Total Attempts: 44

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Midterm - Quiz 4


Questions and Answers
  • 1. 
    Whenever the cpu idle, the operating system must select one of the processes in the ready queue to be executed. The selection process is carried out by the [Blank]
  • 2. 
    The [Blank] is the module that gives control of the cpu to the process selected by the short-term scheduler
  • 3. 
    If the cpu is busy executing processes, then work is being done. One measure of work is the number of processes that are completed per time unit is called [Blank]
  • 4. 
    When a process enters the ready queue, its pcb is linked onto the tail of the queue. When the cpu is free, it is allocated to the process at the head of the queue. The running process is then removed from the queue. Which scheduling algorithm does the above describe? [Blank]
  • 5. 
    Processor afinity states that a processor has affinity for the process which it is currently executing? 
    • A. 

      True

    • B. 

      False

  • 6. 
    A major problem with priority scheduling algorithms is indefinite blocking. A process that is ready to run but waiting for the cpu can be considered blocked. A priority scheduling algorithm can leave some low-priority processes waiting indefinitely. This problem is also called [Blank]
  • 7. 
    The round-robin (RR) scheduling algorithm is designed especially for the time-sharing systems. It is similar to fcfs scheduling, but preemption is added to enable the system to switch between processes, A small unit of time, called a time quantum or [Blank] , is defined.
  • 8. 
    A multilevel queue scheduling algorithm partitions the ready queue into several seperate queues. The process are permanently assigned to one queue, generally based on some property of the process, such as memory size, process priority, or process type. Each queue has its own scheduling algorithm. 
    • A. 

      True

    • B. 

      False

  • 9. 
    The mukltilevel feedback queue scheduling algorithm allows a process to move between queues. The idle is to seperate processes according to the charateristics of their [Blank].
  • 10. 
    On operating systems that supports threads, it is  [Blank] threads-not processes-that are being scheduled by the operating system.
  • 11. 
    Processor affinity takes several forms. when an operating system has a policy of attempting to keep a process running on the same processor-but-not guaranteeing that it will do so-we have a situation known as [Blank] Here,the operating system will attempt to keep a process on a single processor, but it is possible for a process to migrate between processors.
  • 12. 
    One approach to load balancing is [Blank] where a specific task periodically checks the loads oon each processor and-if it finds an imbalance-evenly distributes the load by moving processes from overloaded to idle or less-busy processors.
  • 13. 
    Multicore processors may complicate scheduling issues. Let's consider how this can happen. Researchers have discovered that when a processor access memory, it spends a significant amount of time waiting for the date to become available. This situation may occur for various reasons, such as a cache miss (accessing data that are not in cache memory). This situation is know as [Blank].
  • 14. 
    [Blank] refers to the period of time from the arrival of an interrupt at the cpu to the start of the routine that services the interrupt. When an interrupt occurs, the operation system must first complete the instruction it is executing and determine the type of interrupt that occured. It must then save the state of the current process before servicing the interrupt using the specific interrupt service routine (isr).
  • 15. 
    [Blank] schedulers operate by allocating t shares among all applications. An application can receive n shares of time, thus ensuring that the application will have n/t of the total processor time.
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