CSC103 How Computers Work
Assignment 4

Due Thursday 15 Oct 09 (by midnight)

Please read Assignment and Quiz Rules.

1. Try to explain, as simply and clearly and nontechnically as possibly, why GPS receivers need to receive signals from four satellites to determine their position.


2. List what appear to be the primary differences between 2G and 3G mobile phone communications technology. I am interested here in the features and capabilities: in 2G you could only do this, while in 3G you can do that; 2G had this weakness, which is addressed in 3G with this feature; etc. Try to find five such primary features/capabilities.


3. There are some influential software experts who believe that people should be discouraged from writing programs in Microsoft's new C# language. Can you figure out why this advice is being promulgated? A sentence or two suffices.


4. Write a Scratch program to draw a spiral, producing something like the image shown below. (This is effectively what I hope we will have accomplished in class on Wednesday.) On this one-fourth of the assignment: A- for getting a spiral, A reserved for those who embellish it in some manner, i.e., show me you explored enough to go a bit beyond the minimal.

   Scratch can be accessed in Seelye 212 via Programs | Courseware--General | Computer Science | Scratch. It is also available in McC104, where the TAs will be Thursday afternoon and evening. It may also be downloaded and installed for free on any platform.