Comp150CPA: Clouds and Power-Aware Computing
Quiz 2 Review Answers
Spring 2011

group member 1: ____________________________ login: ______________

group member 2: ____________________________ login: ______________

group member 3: ____________________________ login: ______________

group member 4: ____________________________ login: ______________

group member 5: ____________________________ login: ______________

My quizzes concentrate upon broad understanding and in-class exercises. Problems will be similar to those on the exercises. My quizzes -- by definition -- concentrate on "what things mean" and not on broader impacts; you will not see a so-called "advanced" question on the quiz! I will be emphasizing the following issues from lectures dated 03/09/2011 and beyond:

Here are some sample questions of the kind I am planning:

  1. Please fill in the blanks: in designing a service, one must remember that Map/Reduce is not designed for ____interactive____ use, and that one must typically store the results of a M/R query in a ____distributed datastore/hash table____ instead. In employing a distributed hash table in a cloud application, one must remember that it is typically difficult to employ ____Map/Reduce____ in a DHT. Thus a major part of cloud design is to arrange to ____transfer data____ between the two storage formats.
  2. Please describe what kinds of data needed (in order to program an application) are not coded into a BPMN diagram.
    Answer: It shows the interactions between entities, but does not document the data format or requirements.
  3. Please fill in the blanks: the difference between orchestration and choreography is that orchestration specifies the ____overall____ sequence of events, while choreography specifies ____local____ interactions. The true need for choreography arises from the fact that in BPEL, there is no well-defined notion of a ____subroutine____.
  4. Please fill in the blanks: an ECA model contains ____events____ that describe what happened, ____conditions____ that describe the nature of that, and ____actions____ that describe what to do in that case.
  5. While programmers see the cloud as easing programming, business decision-makers see it as a way of reassigning ____risk____ to another party. This is not a perfect solution, however, because public clouds cannot presently guarantee the ____security/privacy____ that they claim.