Final Week Final Examination

CSci 555 / Neuman Fall 1992
Directions for completing exam

Answer the following three questions:

1. (20 points) The current trend in operating systems is to move functionality out of the kernel, into user space. Describe the reasoning behind this trend. What are some of the potential drawbacks? What operating system functionality must be performed in the kernel and which functions are better performed in user space? How does the structure and the environment of a distributed system affect your answer?
2. (30 points) During the semester we examined the design of several distributed file systems. You have been hired by NASA to design a distributed file system for use between Earth, a space station, and colonies on the Moon and Mars. Using techniques employed by the file systems examined this semester as a guide, sketch your own design for a file system for this environment concentrating on file access mechanisms.
3. (50 points) As part of Bill Clinton's agenda for health-care, you have been hired by department of health and human services to design a new patient information database. Use of this database will reduce health-care costs by automating much of the paperwork presently required for insurance claims. Further, use of this database will improve the delivery of health-care by making patients records available when needed by doctors.
   1. What are the privacy and security requirements of such a system? How do these requirements conflict with the goals of the system and how do they support the goals? What measures would you take to satisfy the security and privacy requirements without preventing access to information that is legitimately required? What specific mechanism would you use to control access to individual records? Why?
   2. The system described will be extremely large, maintaining information on 450 million people. The system will be used in every hospital, doctor's office, and pharmacy in the country. Sketch the design of such a system. Discuss the scalability of your design, paying particular attention to reliability, availability, performance, and any other criteria you deem important.

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