Quiz submission record for quiz4-1-2 at Tue Jul 13 00:42:38 2004:

Your Answer for Question 1:
Essentially, flip-flops are one-bit wide registers that operate on holding a value of 1 or 0 depending on a given input d. In this case of a positive edge-triggering flip-flop, on the rising edge of the clock, the input d is sampled and transferred to the output q. At all other times, the input is ignored. Usually, flip flops cannot change output values instantaneously because time is needed to transfer inputs internally. Thus, the input d must be stable for a short amount of time before the rising edge of the clock and remain stable for a short amount of time after edge (known as the setup and hold time). Once the input is captured, there is still a time lag called the clock-to-q delay in order to transfer the new output value. 

If two D flip-flops were hooked up end-to-end and there was no delay in the wire connecting both of them, there will still be time delays. These occur when the input to the second flip-flop (equal to output of first) is read and then a new output to the second flip-flop is written. In other words, there will still be internal time delays within each flip flop even though the wire connecting them has no delay.   


Your Answer for Question 2:
1-	Elevator operation- various states including going up, going down, stopping at a floor, opening a door, closing a door, etc. all triggered by inputs (pressing elevator buttons). Elevator must handle scheduling and timing correctly to serve the max number of people in the most efficient manner.
2-	Air conditioning/heater- various states of turning on/off based on measuring room temperature
3-	Water! – states of ice/liquid/gas depending again on temperature 



Your unique submission ID is quiz4-1-2-cs61c-ei-1089704558-1612.