Posted: Fri Nov 21

Due: Wednesday 12/3 10:00am

All the instructions for this assignment can be found in README.md after you click the link above to make a new repository. You can also see the instructions here as well.

Overview

Below you will find 2 tasks that will require you to create both text and diagrams, and one that will require you to make an image. You can write and draw the text and diagrams in any way you see fit. You will submit a single pdf file that contains the text and diagrams, and a ppm file for the image. For the pdf, each part should be a separate page, resulting in 5 pages total.

Computer Data & Components (pdf - 3 pages)

You are working on an assignment in DrRacket, you type the following line of code:

(define foo 42)

You save the file. What happened?

Your mission

Provide as much detail as possible in explaining this process. Your explanation should consist of 3 parts:

  1. An ordered list of steps explaining how the text of the file was entered into the computer, where that data was being kept before saving, and what happened to the data when you saved the file.
  2. A diagram showing the computer components you mentioned in part 1 and how the data flowed between them.
  3. Using a standard encoding scheme (specify which one), provide the digital representation of the file, using hexadecimal values.

The Internet (pdf - 2 pages)

You open a web browser, type http://homer.stuy.edu into the address bar, and hit enter. In a matter of seconds, a web page is rendered in your browser. How did that happen?

Your mission

Provide as much detail as possible in explaining this process. Your explanation should consist of 2 parts:

  1. An ordered list of steps explaining how the request and subsequent response was transmitted. If the steps involve a protocol and/or address, explain them.
  2. A diagram showing how that traffic flowed between your computer and homer. The diagram should show:
    • Your computer (at home).
    • Any network device inside your home (router, access point, etc. Not other computers/phones/gaming systems/refrigerators/etc.).
    • Your ISP
    • Stuyvesant’s ISP - Spectrum
    • Stuyvesant’s Gateway Router
    • Homer (homer is connected to the gateway router via a switch)

Image File Encoding (1 image file)

PPM (Portable PixMap) is an image format that represent pixel data as RGB (Red, Green, Blue) triplets in plain text (there are other versions as well). Here is a sample plain text PPM file:

P3
4 3
255
255 0 0  255 0 0  255 0 0  255 0 0
0 255 0  0 255 0  0 255 0  0 255 0
0 0 255  0 0 255  0 0 255  0 0 255

The first three lines make up the file header:

  • P3: Type of PPM, 3-btye RGB, in ASCII.
  • 4 3: Width x Height, in pixels.
  • 255: Maximum value per color

Create a valid ppm file that is at least 100x100 pixels large.

Skills Assessed

Skill Minimal Competency Developing Competency Competency Mastery
13. Number Systems Demonstrates understanding of the decimal number system. Demonstrates understanding of the binary number system. Can convert between decimal and binary number systems. Can work in octal and hexadecimal number systems.
14. Digital Representation of Data Demonstrates an understanding of bits and bytes. Demonstrates how bits can be used to represent integers. Demonstrates how bits can be used to represent characters. Demonstrates how bits can be used to represent other kinds of data (e.g. images, audio)
15. Main Components of Computers Can describe and identify one of the 4 main components of computers. Can describe and identify 2 of the 4 main components of computers. Can describe and identify the 4 main components of computers. Can describe how the 4 main components of computers interact with each other.
17. The Internet Can explain the roles of servers, clients and routers. Can explain how computers are addressed on the internet and what domain names are. Can explain how internet traffic flows between devices. Can explain the role of different internet protocols.