MODD / Mr. Hansen 9/28/2011

Name: _______________________

General Instructions: Raise your hand if you have a question. Write answers in the space provided. If you need additional room, write "OVER" and use reverse side.

Part I. Computation. Please show adequate work. For full credit, and since you have lots of time, cross-check your work by using another base. For example, double-check each hex problem by converting all values to base 10 and performing the operation in base 10 to see if you get the same answer.

1.	Use “10,000 complement” arithmetic to perform the following subtractions in base 10. For your cross-check, use regular elementary-school subtraction.  4286 –3479 ______  2154 –3866 ______
2.	Use two’s complement arithmetic to perform the following hex subtractions. For your cross-check, re-do everything in base 10.  0x48 –0x2F _______  0x4B –0x5C _______
3.	Try to perform the following hex addition (in two’s complement), and explain why the answer is an overflow error.  0x4B +0x5C _______
4.	Convert the following bitstream to (a) big-endian hex and (b) little-endian hex using 16-bit words: 0100101010101111010101010101001101010101010110100101011010100000
(a)
(b)
5.	Perform the following additions in hex: 0BBF +288 _____ 0818 +EEE _____

Part II. Bits, Bytes, Hex, Hertz, and Moore’s Law

6.		Suppose that a certain computer capability costs me $1000 to acquire today. Approximately how far in the future will it be before I can acquire the same hardware capability for about $1? Show your work, and write a sentence or two.
7.		In our class, we define a kilobyte to be ________ bytes or ________ bits.
8.		How many megabytes are in a terabyte? Give both an approximate answer and an exact answer. Exponential notation is acceptable.
	9.		Make a circuit diagram fragment to show the concept of (~A) NAND (~B). Then give a truth table proof to show that (~A) NAND (~B) is equivalent to A OR B.