CS261 Fall 2014: Quiz #2

45 points: 15 per question

This exam is closed notes, closed papers, closed interwebs, closed everything.

Please use whatever word processing software that you'd like to write your answers, but please send me either plain text (≤ 80 characters per line) or PDF. Answers should be emailed to: margo@eecs.harvard.edu.

  1. Once Upon a Time
  2. Pick one of the three papers listed below and write the "once upon a time" description of the paper. You should have approximately 5-8 sentences. Your first sentence must start with "Once upon a time," and your last sentence must end with, "... and lived happily ever after."

    1. Howard: Scale and Performance in a Distributed File System
    2. Rumble: Log-structured Memory for DRAM-based Storage
    3. Wu: SPANStore: Cost-Effective Geo-Replicated Storage Spanning Multiple Cloud Services

  3. Key issue for Cloud-Scale Storage Systems
  4. We've read several papers that present cloud-scale storage systems. Each one takes one particular aspect of the design space, such as:

    1. Consistency
    2. Bandwidth
    3. Cost
    4. Resource utilization

    Which do you think is most important? Why? Write 1-2 paragraphs citing motivation and/or results from papers we have read to support your argument.

  5. Design an Evaluation
  6. You are the Chief Scientist for HotUp, the latest cloud startup. Your company has developed a user account management system that can scale to billions of accounts (individuals might have multiple accounts). Your system provides rock-solid availability, fault tolerance, and consistency semantics that can be adjusted to any criteria the application establishes. You've designed this to mean that the user experience is never confusing. For example, if I change my password and then immediately go to log in, that login must require my new password, not my old one, independent of any failure or from where I log in or anything else.

    Provide an outline of the evaluation section you would write in a paper on this system. Be sure to specify what questions you are addressing, against what systems you'll compare your system, and what benchmarks and/or applications you'll run.

Survey #2

After you complete the quiz, please complete the form available here.