INFORMATION

• This homework assignment covers the material from unit A in our syllabus: Introduction to Computers and Networks.
• You may find it helpful to read ch 1 (p1-15) and ch 3 (p40-55) in the Reed text in order to complete this assignment.
• You can also refer to the lecture notes, posted on the "syllabus" portion of the class web page (see sessions A.1 and A.2).
• You should also find the lab (A.3) useful.

• This assignment is worth 10 points, or 10% of your term grade.

1. Begin by creating a file in Notepad.
   
2. Type your name in the file and your email address.
   
3. Type the answers to the questions (below) in this file.
   
4. Please label your answers so I know which answer goes with which question (e.g., "Part I, question 1").
   
5. When you are finished, email me the file as an attachment (like you did in the lab this week).
   
6. My email address is: sklar@sci.brooklyn.cuny.edu.

PART I. OFF-LINE QUESTIONS

To answer the questions in this part, you do not need to be connected to the Internet. However, you will need to use a computer to run Notepad and type your answers into a file.

1. Define the Internet and the World Wide Web, and explain the difference between them.
   (1 point)

2. Define a server and a client, and explain the difference(s) between them.
   Give some (at least 3) examples of types of servers.
   (1 point)

3. Provide definitions for 5 of the following abbreviations. Give the term that the abbreviation stands for as well as a short explanation of what the term means.
   (1 point)
   
   • CPU
   • RAM
   • URL
   • FTP
   • HTTP
   • IP
   • TCP
   • UDP
   • DNS
   • HTML

4. Define statically stable and dynamically stable robots, and explain the difference between them. For each type of robot, indicate if it is statically or dynamically stable: one-legged, two-legged, four-wheeled, and six-legged robots.
   (1 point)
   

5. List four environmental properties that robot sensors can detect. What type(s) of sensor detects each property?
   (1 point)
   

PART II. ON-LINE QUESTIONS

To answer the questions in this part, you will need to use a computer connected to the internet.

1. (2 points) Trace the route from the computer you are currently using to the web sites listed below. For each site, list the number of hops in the route.
   • http://www.mta.info
   • http://www.brooklyn.cuny.edu
   • http://www.hunter.cuny.edu
   • http://www.columbia.edu
   • http://www.liv.ac.uk
   • http://www.unimelb.edu.au

   Look up each site in your browser and see what it is.

   On dnsstuff, look up the physical location of each of these web servers. (Click on DNS Lookup, as we did in the lab. When you get to the screen with the answer, click on that IP address and you'll see a page called WHOIS that tells exactly where the server is located.)

   In your homework file, for each address, write down what the site is, where the server is located and the number of hops to the site.

   Then, answer this question:
   What can you say about the relationship between the physical proximity of each of these web servers to your current location and the number of hops? i.e., are fewer network hops required to reach machines that are physically closer to you?

2. (2 points) Look up the (numeric) IP address of the following web sites:
   • http://www.amazon.com
   • http://www.amazon.co.uk
   • http://www.amazon.fr
   • http://www.amazon.co.jp
   • http://www.amazon.ca
   • http://www.amazon.de
   • http://www.amazon.at

   Look up each site in your browser and see what it is.

   Look up the physical location of each server.

   In your homework file, for each address, write down what the site is and where the server is located.

   Then, answer these questions:
   What can you say about the relationship(s) amongst these web sites and web servers?
   What did you learn about their physical location(s)?
   Explain how the numeric IP address provide hints to these servers' relative locations.

3. (1 point) Go to http://www.google.com Search for robot. How many results are there (approximate total)? What are the first three non-sponsored URL's found?
   Go to http://www.altavista.com Search for robot. How many results are there (approximate total)? What are the first three non-sponsored URL's found?
   Go to http://www.ask.com Search for robot. How many results are there (approximate total)? What are the first three non-sponsored URL's found?

   In your homework file, list the number of results and top 3 non-sponsored sites found by each search engine.
   What are some of the differences between the three engines?
   Which engine would you use if you were looking for a definition of the word robot?
   Which engine would you use if you were looking for a place to buy a robot?