Suggestion: eliminate 8-bit chunk size for Binary Broadcast Battleship

CS Principles
1

Hi code.org Facilitators,

I have a small suggestion for modifications to the Internet Simulator for this lesson. May I request that you eliminate the 8-bit chunk size padding for this lesson OR allow the students to specify the chunk size. The 8-bit chunk size embedded in this version of the simulator suggests to students that the binary protocol they develop should fit in 8-bits or be a multiple of 8-bits. We teach six sections of CS P here and this particular idiosyncrasy was a source of confusion for the students to the point of irritation.

In previous versions of the Internet Simulator in this Unit, students could tweak the chunk size with a slider. Please make this feature available to the students for this version of the Internet Simulator as well.

Best regards.

Russell Berrett

2

Hi Russel,

Thanks for your feedback. I can see how your students would make this assumption. While the previous version of the simulator allowed students to manipulate chunks, this was to help them understand how computers can interpret bits and give them a sense of overflow errors. After this problem has been understood/solved by the students, the new version of the simulator uses the solution that the real internet has: information sent across the internet is sent in bytes, or 8 bit segments. This does not preclude a computer from interpreting subsets of a byte to mean different things, but the bits are still ‘chunked’ in this way. Perhaps there is a way to make this more explicit for students in the future.

Best,
Madeline

3

Hi @rberrett,

Are you referring to a later lesson?

I opened my Lesson 9 (Battleship) Internet Simulator and it doesn’t show anything about chunk size.

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Frank

4

The default 8 bit chunk size corresponds to the ASCII representation. It would really mess that up if the chunk size could be changed. I do however understand your concern. While I have my students design the binary Battleship Protocol, we never have had time to test it out in the simulator. I agree it would be confusing to come with a 10 bit protocol but then be forced to test it with the 8 bit chunk. It is however how computers work with bits so I would simply say they have to pad it out to 16 bits with 0s.

5

Hi Madeline (and others),

Thank you for the note. I certainly can be very explicit to the students and explain that an 8-bit chunk size (or byte) is the de-facto Internet standard. But that really isn’t the primary Learning Target or even a secondary Learning Target for the lesson. (It is, however, the Learning Target of a later lesson… Lesson 1 of Unit 2: “Bytes and File Sizes”). The learning objective for this lesson is to have the students develop a network addressing protocol and the enforced 8-bit chunk size of the Internet Simulator for this lesson interferes with that learning objective.

Best regards.

Russell Berrett