Comp111 - Quiz 2 Review

Quiz 2 Dec 8, 2009 - closed book

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Quiz 2 topics

Please fill in the blanks. Each blank is worth 5 points.

  1. There are three important statistical distributions important in modelling operating systems. The ________1________ distribution models inter-arrival times for events. Its cumulative distribution function is ________2________ The ________3________ distribution models service times for individual processing requests. These distributions are both ________4________, e.g., service times for ________5________ requests do not affect the service time for the next request.
  2. In Kendall notation, an M/M/infinity queue is one in which arrival times are ________6________, service times are ________7________, and there are an infinite number of ________8________.
  3. Suppose we have an M/M/1 queue with arrival factor λ and service factor μ. This queue has a stable behavior if ________9________<1, but ________10________ when ________9________>= 1. (both blank 9's have same answer). In the latter case, the queue length ________11________ without bound.
  4. A monitor differs from a semaphore in two ways:
    1. It does not ________12________ signals; uncaught signals are ________13________.
    2. It is tied (via a programming language) to a specific ________14________. It is not possible to erroniously utilize a monitor to access a different one.
  5. A(n) ________15________ tells the operating system that attention is needed for a device or peripheral; a(n) ________16________ tells a process that attention is needed. The operating system cannot receive a(n) ________16________ any more than a process can handle a(n) ________15________
  6. Process memory is naturally divided into ________17________ that contain ________18________, each of which contains a fixed number of bytes. A typical byte of memory can be divided into three bit fields including a(n) ________17________ address, ________18________ address, and word address.
  7. Inverted page tables provide a(n) ________19________ efficient mechanism for memory mapping than ________20________ page tables, because the number of pages kept in memory is often far less than the total number of virtual pages available.