CS-343 Assignment 1
Fall 2009

Be sure you keep up to date with the reading assignments for the course. In particular, be sure to complete the first reading assignment before working on this homework assignment.

Once you have completed the reading assignment, answer each of the questions listed below. Instructions for submitting the assignment are after the questions.

1. How many orders of magnitude larger than 520 is 40,000?
2. How many orders of magnitude larger than 520 is 90,000?
3. How many orders of magnitude larger than a picosecond is a millisecond?
4. Convert 250 nanoseconds to picoseconds.
5. Convert 250 nanoseconds to microseconds.
6. Convert 250 milliseconds to nanoseconds.
7. What is the “normal” representation of 5,280µsec?
8. On the average, how many yes/no questions would you have to ask someone if they were thinking of a number between 1 and 10?
9. How many bits would you need to encode the digits 0 … 9?
10. Write out two different binary codes to represent the digits 0 … 9.
11. Calculate the weighted average of the following values; show all work:

    Value	Frequency
    70	200
    80	100
    90	700

12. At Queens College, grade point averages use the number of credits for each letter grade as the weights and the following table to relate letter grades to values:

    Grade	Value
    A+	4.0
    A	4.0
    A-	3.7
    B+	3.3
    B	3.0
    B-	2.7
    C+	2.3
    C	2.0
    C-	1.7
    D+	1.3
    D	1.0
    F	0.0

    What is the GPA of a student who has received A- in 3 courses, B+ in 2 courses, and B in 5 courses, if each course was 3 credits? Show all work.
13. What would be the GPA of the student in the previous question if he had failed a 1-credit course in addition to receiving the grades listed in the question?
14. Show the terms needed to calculate how many bits would be needed to record 10 sec of CD-quality music (stereo). That is, do not do the calculation, but show what numbers would be multiplied together to get the answer.
15. How many bits in 64 KB? Show all work.
16. A disk spins at 10,000 RPM. How long does it take to make one revolution? Answer in seconds, using the correct unit of measure to give a “normal” value with the integer part between 1 and 999.
17. How long would it take to transfer a 250 MB program from disk to main memory if the initial latency is 5 msec and the bandwidth of the channel between the disk and main memory is 600 Mbps? Show all work.
18. How long would it take to execute one million instructions if the average number of clock cycles per instruction is 2.2 and the clock speed is 3 GHz? Show all work.
19. “Computer A is twice as fast as computer B.” What does that mean in terms of how long it takes the two computers to execute a program?
20. “Computer A is 100% slower than Computer B.” Turn that into a meaningful statement, if you can. If you cannot, explain why not.

You may submit this assignment either by writing your answers on paper and bringing it to class on the due date or by putting your answers in an email and sending it to me by midnight on the due date.

If you choose the email option:

1. Put your answers in the body of your email message, not in an attachment.
2. Be sure to put your name in your email message!
3. The Subject line must be CS-343 Assignment 1 to avoid my spam filters.
4. Send your email to either Christopher.VickeryATqc.cuny.edu or vickeryATbabbage.cs.qc.cuny.edu — but not to both.

See the course syllabus for grading and late homework policies.