Suppose there are two ISPs providing WiFi access in a particular café, with each ISP operating its own AP and having its own IP address block. a. Further suppose that by accident, each ISP has configured its AP to operate over channel 11. Will the 802.11 protocol completely break down in this situation? Discuss what happens when two stations, each associated with a different ISP, attempt to transmit at the same time. b. Now suppose that one AP operates over channel 1 and the other over channel 11. How do your answers change?

After you clean an engine with hot water spray, it seems to stall; when it doesn't stall, it's idling noisily. technician a says to check for loose bolts on the flex plate near the torque converter. technician b says to wipe down the spark plug wires and the distributor cap. who is correct? a. technician a b. both technicians a and b c. technician b

Which of the following statements is false? a. a class can directly inherit from class object. b. if the class you're inheriting from declares instance variables as private, the inherited class can access those instance variables directly. c. a class's instance variables are normally declared private to enforce good software engineering. d. it's often much more efficient to create a class by inheriting from a similar class than to create the class by writing every line of code the new class requires.

When making changes to optimize part of a processor, it is often the case that speeding up one type of instruction comes at the cost of slowing down something else. for example, if we put in a complicated fast floating-point unit, that takes space, and something might have to be moved farther away from the middle to accommodate it, adding an extra cycle in delay to reach that unit. the basic amdahl's law equation does not take into account this trade-off. a. if the new fast floating-point unit speeds up floating-point operations by, on average, 2ă—, and floating-point operations take 20% of the original program's execution time, what is the overall speedup (ignoring the penalty to any other instructions)? b. now assume that speeding up the floating-point unit slowed down data cache accesses, resulting in a 1.5ă— slowdown (or 2/3 speedup). data cache accesses consume 10% of the execution time. what is the overall speedup now? c. after implementing the new floating-point operations, what percentage of execution time is spent on floating-point operations? what percentage is spent on data cache accesses?