CMPSCI 677 (Spring 2008): Homework 2

Due: In-Class, Feb 21 2008

Web posted: Feb 14, 2008
  1. Explain what is meant by distribution transparency. The text book lists seven forms of transparency, please give one example for each of them.

  2. What is the main scalability problem with a video conference application?

  3. We know replication and caching are two important scaling approaches. However, they bring us with another scalability problem. What is that problem? How can it be solved?

  4. We already gave some examples of distributed pervasive systems: home systems, electronic health-care systems, and sensor networks. Extend this list with two more examples.

  5. Use one example to show how to organize a web site into a three-tiered architecture. What each tier is expected to do?

  6. Not every node in a peer-to-peer network should become superpeer. What are reasonable requirements that a superpeer should meet?

  7. Give a technical argument why the tit-for-tat policy as used in BitTorrent is far from optimal for file sharing in the Internet.

  8. It makes sense to limit the number of threads in a server process. Give two reasons for this?

  9. Explain why a type 1 hypervisor can not be built on older Intel machines?
  10. Virtual machines are useful in migrating applications between different servers. Why is this easier than general solutions for strong mobility?

  11. Consider a process P that requires access to file F which is locally available on the machine where P is currently running. When P moves to another machine, it still requires access to F. If the file-to-machine binding is fixed, how could the system wide reference to F be implemented?