Please place your answers to this homework assignment in a file named hw8.txt or hw8.pdf and submit it using the appropriate submit script.

1. Must collaborative interfaces require that users be cooperative, at least as discussed in class? Do not just answer yes or no. Give a supporting explanation.

2. Access in a distributed system:
   1. What is the advantage of using hierarchical objects (e.g., dividing a word processing document into sections and then into subsections or dividing a spreadsheet into column groups) to control access in a distributed application?
   2. What is the disadvantage of using hierarchical objects?

3. Floor control:
   1. What does the term "floor control" mean in the context of distributed interfaces?
   2. Why might you want to use floor control in a distributed application?

4. In class we discussed the following five types of ways to distribute the MVC model:
   1. Pixel/Event Distribution
   2. Graphics Package Layers
   3. Programmable API
   4. Model/Data Distribution

   For each of the following applications, describe which of the above distribution techniques is being used:

   1. ________________ Java applets
   2. ________________ Virtual software, such as software to display a Microsoft Windows desktop on Linux and Macintosh machines.
   3. ________________ HTML forms
   4. ________________ X Windows
   5. ________________ A spreadsheet application where each user has a local copy of the spreadsheet and a server maintains a master copy of the spreadsheet and coordinates updates to the spreadsheet.

5. Which disadvantage(s) of the Graphics Package Layers and Pixel/Event Distribution models are remedied by the Programmable API technique?

6. Pixel/Event Distribution versus Graphics Package Layer.
   1. Which disadvantage(s) of the Pixel/Event Distribution technique is remedied by the Graphics Package Layer technique.
   2. What kind of flexibility do you give up when you use the Graphics Package Layer technique, rather than the Pixel/Event Distribution technique?

7. Programmable API versus Model/Data Distribution.
   1. Which disadvantage(s) of the Programmable API technique are remedied by the model/data distribution technique?
   2. What implementation issue is introduced by the model/data distribution technique?
   3. What are two ways to solve this implementation issue?