Home CS439

CS439: Principles of Computer Systems

Homework 9, Part 1

Due: 8:45a Friday, April 17, 2015

Part 1 of the homeworks must be submitted electronically. Please refer to the homework turnin instructions.

  1. Pooh Software Ltd. is selling a file system that uses a UNIX-like file system with multi-level indexing. For more reliability, the inode array is actually replicated on the disk in two different places. The intent is that if one or a group of sectors that are storing either replica of the array become bad, the system can always recover from the replica. Discuss the effect of having this replicated data structure on performance.
  2. How does a journaling file system maintain file system consistency even in the event of a crash? Name an example of a journaling file system.
  3. Using the traceroute command, trace the hops a packet takes from one of the UTCS machines to a website in Europe. Inspect the trace. What do you notice? Do you see any machines you recognize? ISPs? Cities? Please be sure to tell us what website you used.

    Perform the trace again. How does the second time affect the output?

  4. Which is the best (fastest) network on which to implement a remote-memory read that sends a 100 byte packet from machine A to machine B and then sends a 8000 byte packet from machine B to machine A?
    1. A network with 200 microsecond processing overhead, 10 Mbyte/s bandwidth, 20 microsecond latency
    2. A network with 20 microsecond processing overhead, 10 Mbyte/s bandwidth, 200 microsecond latency
    3. A network with 20 microsecond processing overhead, 1 Mbyte/s bandwidth, 2 microsecond latency
    4. A network with 2 microsecond processing overhead, 1 Mbyte/s bandwidth, 20 microsecond latency
  5. Describe the steps necessary to prepare a server to accept connections. How does it accept a connection?