Describe the user interface in other high-technology devices commonly found in the home or office, such as a DVD player, audio system, television, copier, or microwave oven. Pick one specific device and discuss how well its interface is designed and how easy it is to use. Does the device use the same techniques as computer system interfaces, such as menus and icons? 17. Is the following pair of statements legal or illegal? Explain why. LABEL: DATA 3 LABEL: DATA 4 If it is illegal, will the error be detected during pass 1 or pass 2 of the assembly process? 18. What are some drawbacks in using passwords to limit access to a computer system? Describe some other possible ways that an operating system could limit access. In what type of application might these alternative safeguards be appropriate? 19. Why are authorization lists so sensitive that they must be encrypted and protected from unauthorized change? What kind of damage can occur if these files are modified in unexpected o unplanned ways? 20. Assume that any individual program spends about 50% of its time waiting for 1/0 operations to be completed. What percentage of time is the processor doing useful work (called processor utilization) if there are three programs lcaded into memory? How many programs should we keep in memory if we want processor utilization to be at least 95\%6? 21. Here is an algorithm for calling a friend on the telephone: Step Operation 1. Dial the phone and wait for either an answer or a busy signal 2. If the line is not busy then do Steps 3 and 4 3. Talk as long as you want 4. Hang up the phone, you are done 5. Otherwise (the line is busy) 6. Wait exactly 1 minute 7. Go back to Step 1 and try again