UNIVERSITY OF HOUSTON Department of Computer Science COSC 6360: Operating Systems FINAL EXAMINATION Part I: General Questions QUALIFYING EXAMINATION Part A: Graduate Topics May 16, 1991 CLOSED BOOK: You may have with you two sheets of notes. 1. What can be done to reduce the overhead of Remote Procedure Calls? (20 points) 2. How would you implement replicated files in a distributed file system supporting the IMMUTABLE SHARED FILE SEMANTICS? Describe in some detail (a) your definition of the most current version of a file, (b) your treatment of network partitions, and (c) your implementation of replicated directories. UNIVERSITY OF HOUSTON Department of Computer Science COSC 6360: Operating Systems FINAL EXAMINATION Part II: Specific Questions May 16, 1991 CLOSED BOOK: You may have with you two sheets of notes. 1. What makes CONDITIONAL CRITICAL REGIONS impossible to implement efficiently? (10 points) 2. Would it be a good idea to implement ALL Remote Procedure Calls as ATOMIC TRANSACTIONS? Why? (10 points) 3. Why are GUARDED COMMANDS an ESSENTIAL part of CSP's design? (6 points) How do UNIX IPC packages solve the same problem? (4 points) 4. What are the advantages and disdavantages of Andrew's CALLBACK mechanism? (10 points) 6. (a) What are the major limitations of Sun's NFS in terms of administrative complexity, performance and sharing semantics? (8 points) (b) How does SPRITE solves these problems? (10 points) (c) Give ONE major weakness of SPRITE? (2 points)