THE MAGAZINE FOR COMPUTER APPLICATIONS
Circuit Cellar Online offers articles illustrating creative solutions
and unique applications through complete projects, practical
tutorials, and useful design techniques.

WHAT'S YOUR ENGINEERING QUOTIENT?

Problem 1—What is a current mirror? Explain with a circuit that uses NPN transistors.

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Problem 2—A NOP (no operation) instruction is included in most of processors. Is just idles the CPU hardware for one instruction cycle and does nothing useful. Why is it needed?

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Problem 3—Calculate the average memory access time for a computer system using cache memory, given that the cache hit ratio is 'h', main memory access time is t_m, and cache memory access time is t_c.

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Problem 4—What is picoJava?

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Problem 5—What is the difference between the "frontside bus" and the "backside bus" on an Intel Pentium® microprocessor?

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Problem 6—The usual way to set a register of a processor to zero is to move the value into the register using an instruction like MOV AX,00. But the MOV instruction requires 2 bytes and a memory fetch for the data. Can you suggest a more efficient way to set a register to zero?

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Problem 7—You are driving at night behind another car. As the other driver approaches an intersection, he uses his brakes and his left taillight brightens as usual, but the right taillight goes dark! What exactly is wrong with his car's wiring?

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Problem 8—You are presented with a black box with three terminals, hooked up as shown below. If either switch is turned on alone, the bulb lights, but if both switches are turned on, it does not.

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