I stashed this away while reading an ARPA bulletin board in school a decade ago. It was posted by a Xerox PARC hacker (you know, the guys who *invented* EtherNet) as a test called "the systems qual." Dated: 2 September 1982 1 Pick from the following pictures the one which most accurately represents a computer: A. B. C. D. Answer: D. 2. What is the limiting factor on the speed of paging in modern computer architectures? Answer: the number of meters of coax between your 8080 and your floppy disk. 3. Name 100 advantages of personal machines over timesharing machines. Name 1 advantage of a timeshared machine over a personal machine. There were a lot of complaints about this question, and we admit it was intended as a trick. Several of the people who passed spent over an hour trying to think of the advantage of timeshared machines. 4. What is the primary design consideration in designing a modern computer system? Answer: How to maximize the ratio of coax to silicon. 5. What was the most important invention for modern computing? A. ECL and high level logic B. Advanced cooling technologies C. Video Disks D. Cache memories E. Coaxial cable Answer: E. 6. What is the most important function of a modern computer system? Answer: the mail server 7. What is the most important measure of the sophistication of a modern operating system? Answer: the complexity of the mail headers it produces. 8. What is the most reasonable power dissipation in modern computers: A. equivalent to a 2000 megaton nuclear device (e.g. CRAY-1) B. equivalent to the output of the Hoover Dam (e.g. S-1 MARK IIA) C. equivalent to a room full of toaster ovens (e.g. a DEC 2060) D. equivalent to a sexually satiated male mosquito in a room at absolute zero (e.g. a single board 68000 connected to 90 miles of 300 ohm coax). Answer: D. (The next question is from Sue Owicki) 9. Define: A is 'strongly hyperhyperimmune' if A is infinite and there is no recursive f such that (^Tu)[W(f(u)) ^R A ^Z empty] & (^Tu)(^Tv) u ^Z v => W(f(u)) ^R W(F(v)) = empty]. A. show that if A is strongly hyperhyperimmune then A has no infinite retraceable subset. B. show that if A is strongly cohesive then A is strongly hyperhyperimmune. Answer: A - obvious; B - immediate corollary of A. 10. What are the design considerations in a modern display? Answer: it must display 10^49352 points per inch and run at least at 2 baud (to support the new, high speed 8080's out on the market). 11. Describe the new generation of 'supercomputers'. Answer: the MC68000 is... 12. Name the institutions where the most progressive computer systems work is being performed. Answer: Bell Labs (C and Unix) because they are part of the phone company and, hence, like copper wire; Xerox (Altos) because they have cornered the world coax market. 13. What units are used to measure the performance of modern computers? Answer: TIPS - Thousandths of Instructions Per Second. 14. (Methodology> Why is it that large computers (e.g. Cray-1) are no longer of interest to systems people? Answer: They run too fast to understand and to use coax effectively. Running one of these computers on an ultra-high speed network (3 megabit net) would swamp it. 15. Where are the reliability issues centered in modern computers? Answer: UHF connectors 16. Define a 'large program'. Answer: A program that is more than 1/2 a page long or that has less than 10 lines of declarations for each line of code. 17. How may programs have you written? Passing answer: < 10 Failing answer: > 15 Conditional answer: 10 > x > 15 18. What is the largest program that you have ever heard that a real computer scientist has written? Answer: a mail server 19. Why is synchronization research better performed on small, modern computers connected by a network? Answer: The coax slows things down so much that you don't have to worry about deadlocks. 20. Some people say that extremely large programs (> 500 lines) require very large computers. How do you answer them? Answer: If they know what they were doing they wouldn't need a large machine. The fact that they write such large programs means they are doing the wrong thing. 21. What should we do with people who believe in huge timesharing machines that run like hell and who want to write gigantic programs. Answer: Fail them on the systems qual.