CSS 434
Group Discussion

Instructor: Munehiro Fukuda
Discussion dates: see the syllabus


1. Purpose

Group discussion intends to help you understand other students' paper-review presentation and class materials. Three or four students form one group to discuss about one topic given by the professor and present their discussions.

2. Topics

No. Discussions Grade Topics
1 Process Migration, Time and Global States 1%
  1. Group 1:
    • Consider two distributed snapshot algorithms such as Samadi's and Mattern's algorithms. Discuss their pros and cons.
  2. Group 2:
    • Solve textbook Q14.14
  3. Group 3:
    • Compare Timewarp and SPEEDS in terms of performance, process creation/termination, dynamic memory allocation, and I/O handling.
  4. Group 4:
    • Solve textbook Q14.15
  5. Group 5:
    • What features of the Java language system facilitated design and implementation of mobile agents? What features of the Java virtual machine does not allow strong migration?
2 Distributed Shared Memory 1%
  1. Group 1:
    • Compare Ivy and Dash in terms of considtency models, shared-data granularity, HW/SW implementation, false sharing, and implementation. What types of applications can Ivy and Dash benefit respectively?
  2. Group 2:
    • Solve slide p24's non-turn-in exercise 1.
  3. Group 3:
    • Compare distributed shared memory and message passing (such as MPI) in terms of programmability and performance. Discuss about their pros and cons using two types of applications: computer graphics such as 3D ray tracing and spatial simulation such as molecular dynamics.
  4. Group 4:
    • Solve slide p24's non-turn-in exercise 2.
3 Distributed File Systems 1%
  1. Group 1:
    • Compare NFS and AFS in terms of file-accessing models, file-sharing semantics, modification propagation (write through or delayed write), server-side/client-side caching, and client/server-initiated validation
  2. Group 2:
    • Discuss about the pros and cons of Amazon S3's bucket in terms of its size, flat structure, and data consistency model.
  3. Group 3:
    • Discuss about the pros and cons of backward transaction and forward transaction.
4 Fault Tolerane 1%
  1. Group 1:
    • Could the gossip architecture be used for a distributed computer game as described below? The players move figures around a common scene. The state of the game is replicated at the players' workstations and at a server, which contains services controlling the game overall, such as collision detection. Updates are multicast to all replicas. (Textbook Q18.11)
  2. Group 2:
    • Suppose that a user wants to use Gossip for grid-computing middleware where s/he runs a massively parallel application with a large number of remote computers. Each process running at a different computer has a postive sequential identifier, periodically takes an execution snapshot, monitors its logical neighbor with a one-larger identifier, and resumes this neighbor at a new computer if it has crashed for some reason. Discuss if Gossip can faciliate this fault tolerance in grid computing or not.
  3. Group 3:
    • The quorum-based replication protocol can address network partition problems. Why didn't Code use this protocol? Explain the reason.
  4. Group 4:
    • Suppose that a user wants to use Coda for grid-computing middleware where s/he runs a massively parallel application with a large number of remote (network-detachable) computers. Each process running at a different computer has a postive sequential identifier, periodically takes an execution snapshot, monitors its logical neighbor with a one-larger identifier, and resumes this neighbor at a new computer if it has crashed for some reason. Discuss if Coda faciliate this fault tolerance in grid computing or not.

3. Discussion and Presentation

Approximately 20 to 25 minutes will be given for a group discussion. The professor will give each group a piece of scratch paper on which they summarize their discussions. Using this paper, a group representative is supposed to present the discussion to other students and will receive 0.1 points as extra credits.