FFR: For Fun Reference.

What's the signal speed in the wire?
1.Electricity travels in wire at the speed of light(c) while the light couldn't achieve the speed of light c in the air.
2.Electrons travels at the speed of 0.25 milimeter/second.
3.A signal, the 0/1 representation of voltage, passes a logic gate within the propagation delay(a few nanoseconds, possibly much less than 1ns).
4. For a 1GHz processor, the clock cycle is 1ns. The signal can only travel 30 centimeters in the wire or pass through one logic gate in one clock cycle if the propagration delay of the gate is 1ns. Oops!

What's the GPS price and how it works?
1.It could be less than $100 with accuracy less than 3 meters in open area.
2.It uses the time interval from the satellite to the receiver to calculate the distance. Of course, it needs accurate synchronized clocks, because it doesn't send out signals.
3.There are 24 satellites positioned in the space. But the GPS receiver only needs signals from four of them to calculate the receiver's position.

What can happen to the wireless signal?
1.The signal can change direction and intensity via reflection, refraction and diffraction.
2.The signal can change velocity and intensity in different media.

What does OOP mean?
1.Object-oriented-programing. It supports encapsulation, inheritance and polymorphism.
2.Out-of-Order Processor. It supports out of order issuing and execution of instructions.
3.Out-Of-Pocket. People in Canada fully enjoy their out-of-pocket expenses.

What's the waterfall model and spiral model in software development?
They include the following stages:
1.Requirements(10%) 2.Specifications(10%) 3.Design(15%) 4.Documentation(10%) 5.Coding(15%) 6.Testing/Debugging(40%) 7.Maintenance(120% of all the previous stages)
1'.Percentage at above line indicates the efforts and time contributing to the whole life cycle of the software.

What's the No. 1 supercomputer in 2005?
IBM BlueGene/L United States Rmax (GFlops) 136800 IBM Application area: Not Specified Installation Year: 2005
System Details Processor: PowerPC 440 700 MHz (2.8 GFlops) Topology/Interconnect: Proprietary Operating System: CNK/Linux Processors: 65536 Rpeak (GFlops): 183500 Rmax (GFlops): 136800