CSE 221: Homework 1

Winter 2005

Due: Thursday, January 27, 2005 in class

Answer the following questions. Support your answers with material from the referenced papers, or with your own critical arguments, as appropriate. I am interested in your justifications as much as the answer itself. There may not necessarily be a "right" answer, although some answers may be easier to justify. Finally, do not use shorthand -- write your answers using complete sentences.

  1. The Multics paper lists a set of principles for protection in an operating system. Critique Hydra according to those principles. To what extent does Hydra implement each principle?
  2. Critique Pilot according to the same principles. For each, if you think that Pilot does not implement the principle, explain whether it is important (or not) that it does not.
  3. Both Pilot and Swift used typesafe languages to implement the system, and both reported significant benefits in doing so. Why do you think the operating systems we use are not implemented in type-safe languages?
  4. Pilot made a strong argument for tailoring the design and implementation of operating systems to personal computers. Why do you think we still run timesharing systems on our PCs?