Your write-up for each lecture should consist of a very short essay-style answer. Turn in your write-up via email by sending them to the instructor before 11 a.m. on the day of the class where we discuss the paper, with only 736 and the due date in the subject line (e.g., 01/25). Late write-ups will automatically receive a null score. Write-ups must be in plain text without any attachments. More hints on a good write-up include:
  • Answer the specific question that has been posted.
  • Write up to 3 paragraphs. Each paragraph should be between 3-5 sentences.
  • Do not quote large parts directly from the paper.
  • Use your own words and thoughts.

  1. Due Monday, 12/2 - Opt-Safe
    What is one strength of this work (or paper)? What is one weakness of this work (or paper)?
  2. Due Friday, 11/22 - Scalability
    Come up with your own question(s) to answer. You can either answer two separate questions (one for each of the papers) or answer a single question that covers both papers.
  3. Due Wednesday, 11/20 - CFS
    The Cooperative File System (CFS) is designed to be robust to servers entering and exiting the system. Describe what must happen when a server fails.
  4. Due Wednesday, 11/13 - MapReduce and GFS
    How does the MapReduce programming model interact with the Google file system (GFS)? Where does MapReduce use GFS and where does it not? What are the performance and reliability implications of using GFS or not?
  5. CHANGE!!!! Due Monday, 11/11 - NFS vs AFS
    Why might someone prefer to use NFS over AFS? Why might someone prefer to use AFS over NFS? You may consider any interesting issues (e.g., the relative performance of different types of workloads).
  6. CHANGE!!!! Due Friday, 11/08 - Differentiated I/O
    What ONE question would you like to ask one of the authors?
  7. Due Wednesday, 11/06 - Lottery and Resource Containers
    How can resource containers be used with lottery scheduling? Describe how a system combining both ideas would work. Do they seem like a good match for each other or not?
  8. Due Friday, 11/01 - Eraser and Scheduler Activitations
    Design two questions for each paper that you think would be interesting to discuss in small groups during lecture.
  9. Due Wednesday, 10/30 - Monitors
    The Mesa system forced the developers to address a number of the practical issues associated with monitors and condition variables. Describe some aspects of the implementation of synchronization primitives in Mesa that were not addressed by C.A.R. Hoare.
  10. Due Wednesday, 10/23 - VMware ESX Server
    Memory management is much trickier in the VMware ESX Server (compared to Disco) because of VMware's goal of running unmodified operating systems. Discuss some of the techniques VMware developed to handle this goal/requirement.
  11. Due Monday, 10/14 - RAID and AutoRAID
    When is RAID-1 the best match for a workload and environment? When is RAID-5?
  12. Due Thursday, 10/10 - RAMCloud
    If you could ask the authors TWO questions, what would they be?
  13. Due Wednesday, 10/9 - OptFS
    What are the pros and cons of turning off flush commands in a traditional journaling file system, such as ext3? What are the differences between the asynchronous durability notification used in OptFS and a flush command?
  14. Due Monday, 10/7 - ZFS
    What does ZFS do to detect and recover from data (and meta-data) that is lost or corrupted on disk? Despite these techniques, when might a user receive bad data that was stored in ZFS?
  15. Due Friday, 10/4 - IRON FS
    Consider Figure 2 (File System Failure Policies) on page 8 of the paper. First, describe how the data was collected for this graph. Second, at a high level, summarize what the data shows overall. Third, pick a specific entry that you find interesting (or small set of entries) and discuss why the file system behaves as it does.
  16. Due Wednesday, 10/2 - LFS
    What type of workloads do you expect will perform better with LFS than FFS? Why? What type of workloads do you expect will perform worse with LFS than FFS? Why?
  17. Due Monday, 9/30 - Files Not Files
    After reading this paper, what are three questions that you would like to ask one of the authors? The questions can be to explain something you didn't understand, to go into more details or elaboration on a specific point, or about potential follow-up work.
  18. Due Friday, 9/27 - Hydra or Exokernel
    You may answer either question that you choose.
    1. HYDRA: What are the strengths and weaknesses of using capabilities as a general protection mechanism?
    2. Exokernel: Imagine that you are implementing a library OS, focused on improving some specific workload of your choosing. Describe a policy that your libOS may apply to optimize your target workload.
  19. Due Wednesday, 9/25 - Nooks
    Imagine that you would like to use a new extension (e.g., a new device driver) in a system with Nooks. In the best case, what work will you need to do to use the new extension with Nooks? In the worst case, what work will you need to do?
  20. Due Friday, 9/20 - Disco
    Virtual machine monitors (VMMs) such as Disco impose some overheads on running workloads. Describe some of time and space overheads that occur in Disco.
  21. Due Wednesday, 9/18 - Mach
    As stated in the paper "Physical memory in Mach is treated primarily as a cache for the contents of virtual memory objects." What does this statement mean? What are the implications of treating physical memory as a cache? Are there any advantages or disadvantages to this approach?
  22. Due Friday, 09/13 - VAX VMS
    What are the roles of the pager versus the swapper in VAX VMS? What information is needed by both the pager and the swapper? Is there any information that one must track that the other does not? If so, what?
  23. Due Wednesday, 09/11 - Disks and FFS
    In what ways did the performance characteristics of the disks of the time influence the design of FFS?
  24. Due Friday, 09/06 - THE, Nucleus, and UNIX
    In your own words, describe how the definition of a process differs across THE, Nucleus, and UNIX. You may want to discuss if different features or functionality (related to processes) are included across the three systems, or how processes are managed differently across systems.


Fall 2013
Time: MWF 1:00-2:15
Room: 119 Noland

Prof Andrea Arpaci-Dusseau

Office Hours
Tuesday 10:00-11:00
Friday 2:30-3:30
7375 Computer Sciences
Email: dusseau "at"

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