CSC103 How Computers Work
Take-Home & Paper: Discussion & Best of the Week

I was pleased with the classes performance on both the Paper and the Take-Home. The average grades were right near the B+/A- border, and almost no one did terribly. I thnk that either route you took ended up being a significant learning experience, which is always the goal.

Paper Topics:

• cell phones
• tiny surveillance video cameras
• industrial robotics
• ASIMO humanoid robot
• social networking
• cloud computing
• MacOS vs. Windows
• the Xbox
  

Paper class average: 89.63 → high B+

Take-Home class average: 89.57 → high B+

Here are representative good answers drawn from various submissions. I make only a few additional remarks myself.

1. Grace Murray Hopper . Lucia Villagra:
   • She was part of the team developing the UNIVAC I.
   • It was her idea that programs could be written in a language that was close to English rather than in machine code or languages close to machine code.
   • She developed the first compiler for a computer programming language.
   • She pioneered the implementation of standards for testing computer systems and components.
   • She was one of the first programmers of the Harvard Mark I computer.


2. Binary
   • 10010112 = 75
   • 100101102
   • Add zero to right-hand end of binary number


3. MP3 psychoacoustics. Christine Cobden:
   • The MP3 exploits the psychoacoustics of the human ear to achieve excellent compression without loss of audio quality. The MP3 file achieves this by acknowledging the actual range of human hearing capacity and filters out that which cannot be heard readily or sufficiently, and reducing “extra noise” that will barely be missed. This then strengthens the sound of the music that remains and clarifies it – all with reducing the size of the file without reducing the quality of what our human ear enjoys.
   • JOR: In general I would have liked more info on the psychoacoustics aspects: loud sounds mask quiet sounds, similar simultaneous pitches cannot be distinguished, etc.


4. 1 TB disk over a 100 Mbps cable.
   • Sarah Allen: 1 Terabyte = 1,024 GB = 1,048,576 MB = 1,073,741,824 KB = 1,099,511,627,776 Bytes = 8,796,100,000,000 bits = 8,796,100,000Kb = 8,796,100 Mb.
   • Divide by 100 Mbps → 87,961 seconds (approximately 24 hrs!).
   • JOR: The factor between TB, GB, MB is 1024. But 100Mbps really means 100 million bits per second. Quite confusing, I know. If you only made 1000 vs. 1024 errors, you should have ended up with 83,000 seconds or so.


5. Design a circuit. Sarah Allen:
6. 


7. Design a circuit. JOR: This was difficult to think through, but in fact there is a succinct solution. Hu Hsing Su:
8. 


9. batteries on the motherboard. Hoa Lan Vo:
   • The CMOS (complementary metal-oxide semiconductor) battery is located on the computer's motherboard. When that battery starts to run out of power, unpleasant things will happen. For example, you may notice the PC keeps forgetting the date and time, resetting them to midnight on Jan. 1, 1990, perhaps. Or the PC suddenly can't access certain peripherals. Or it may refuse to boot at all, displaying a "CMOS Checksum Error" or "System Configuration Lost" message instead.


10. detect the atmospheric distortions. Cassandra Chao:
    • A laser beam transmitted from a telescope into a layer of mesospheric sodium, the beam is resonantly backscattered from the amount of active sodium atoms, acting as a “guide-star” whose position and shape are well- defined except for atmospheric distortion. The telescope collects the light from the guide-star and a wavefront sensor determines the distortion caused by the atmosphere. The wavefront sensor measures the distortions the atmosphere has introduced on the timescale of a few milliseconds.
    • JOR: What most everyone missed here is the need for a guide star, which is either a real star nearby the one under scrutiny, or a "created" guide star, created by shooting a laser beam high into the atmosphere and having it bounce back from a special atmosphere layer that contains sodium atoms that are idea for this reflection. It was quite difficult to penetrate the technical jargon to figure out what is really going on.


11. Write a Scratch program to draw a series of nested squares. Cassandra Chao:


12. Moore's Law and technological "singularity". Xiao Huang:
    • Explanation: Moore’s Law describes a long-term trend in the history of computing hardware, in which the number of transistors that can be placed inexpensively on an integrated circuit has doubled approximately every two years. When similarly applied to the technical term, many futurist believe that exponential improvement described by Moore's law will ultimately lead to a technological singularity: a period where progress in technology occurs almost instantly.
    • Support: Futurist Ray Kurzweil generalizes singularity to apply to the sudden growth of any technology, not just intelligence; and argues that singularity in the sense of sharply accelerating technological change is inevitably implied by a long-term pattern of accelerating change that generalizes Moore's law to technologies predating the integrated circuit.
    • Criticize: Eliezer Yudkowsky has suggested that many of the different definitions that have been assigned to Singularity are mutually incompatible rather than mutually supporting. For example, Kurzweil extrapolates current technological trajectories past the arrival of self-improving AI or smarter-than-human intelligence, which Yudkowsky argues represents a tension with both I. J. Good's proposed discontinuous upswing in intelligence and Vinge's thesis on unpredictability.