Distributed Systems 
Fall 2008
Exercise 2

Tanenbaum Ch 1 or CoDoKi Ch 1,2
Tanenbaum Ch 2, 4 

Topic: Transparency and RPC

1. Give an example of each transparency type. Use as examples
   a) a distributed file system
   b) printing service (a group of printers)
   which are intended for mobile-user applications.
   Why is it not always a good idea to implement transparency?

2. Create a small application example where you utilise RPC calls (in
Java environment). Explain the principles of RPC.

3. a) Give a detailed step-by-step description about the execution of
   the remote procedure call "call foo(data, result)
   (who does what, based on which information, obtained from where?).
   b) In a remote procedure call, how can you implement a "call by
   reference" parameter (the general idea: during its execution the
   procedure uses the value of the "original" variable). When will
   your implementation lead to an erroneous state of the computation?
   How could you implement "call by reference" in a rigorous way?