UNIVERSITY OF HOUSTON Department of Computer Science COSC 6360--Operating Systems MIDTERM EXAMINATION March 9, 1999 This exam is closed book. You can have two sheets (i.e., four pages) of notes. 1. UNIX is said to be a system using the toolkit approach. Why? (5 points) What feature of the UNIX file system made that possible? (5 points) 2. How would you simulate a page-referenced bit on an architecture lacking it but having (a) a missing bit set to one when the page is not in main memory and (b) an x bit in the page table that you can use as you want? Be specific. (10 points) 3. Compare and contrast the page replacement policies of VMS and Mach. (10 points). Which one is the best suited for UNIX and why? (5 points) 4. What are shared libraries? (5 points) What is their major advantage?(5 points) 5. What is partial-subblocking? (5 points) What is its major advantage? (5 points) Describe in some detail page table organization that would support partial-subblaocking with a blocking factor of 8? (10 points: you will loose five points if your answer does not include a diagram) 6. What is the difference between eager release and lazy release consistency? (10 points) 7. Compare and contrast the ways Munin and Treadmarks interact with the underlying operating system. (10 points) 8. What is the main purpose of a shuttle in the Spring Kernel? (5 points) 9. What are the two basic components of an exokernel based system? (2×2 points) What are their major functions? (2×3 points)