EBoard 02: Getting started with our lab equipment (Section 1)

Warning! You are being recorded (and transcribed) (provided the technology is working correctly).

Today’s start-of-class procedure

• Take one of the business cards.
• Identify where the named computer is.
• Drop the business card in the jar.
• Navigate to that computer.
• Today only: Start the lab.
• When a second person arrives, introduce yourself.

Note: If you need to sit in a particular area of the classroom, let me know and we’ll work things out in the future.

Approximate overview

• Lots of administrative stuff, no attendance [10 min]
• Questions [5 min]
• Debrief on last class [10 min]
  • The pre-activity activity [5 min]
  • The activity [5 min]
• Lab one: Get yourself setup for MathLAN. (Both partners.) [15 min]
• Lab two: Play with DrRacket [30 min]
• Layers! [10 min]

Administrative stuff

Introductory notes

• Something that didn’t end up in the syllabus and should have: I’m not only bad at remembering names, I’m likely to swap them. (There’s a longer statement that’s now in the syllabus.) I apologize.
• I should also report that I believe that all teaching is performative.
• I make it a practice to call on students using a set of cards with names on it.
  • I use this process to give you practice “thinking on your feet”, as it were.
  • I also use this process to help everyone realize that they are not the only one who is puzzled.
  • And I use the process to push you a bit.
  • Feel free to say “I’m not sure” or “I’d prefer not to answer.”
  • If you don’t want to be called on in class, please let me know.
• The csc151 library (which you’ll learn about in lab today) is updated regularly. Each time you sit down to work, you should try to update the version you have. The lab will tell you how.
  • Also: Let me know when you encounter bugs or unexpected behavior.
• You should only submit the reading checks with double-daggers (‡).
• Consider setting up password reset on https://passwordreset.grinnell.edu.
• Readings are taking people longer than I’d expected. If they continue to take many people more than an hour, I’ll find ways to cut back.

Upcoming activities

Scholarly

• Tuesday, 2025-01-28, 4:00–5:00 p.m., TBD. CS Candidate Talk: Intelligent Tutoring Systems and Equity in Math Education.
• Thursday, 2025-01-30, 11:00 a.m.–noon, JRC 101. Scholars’ Convocation: The Once and Future Grinnell College.

Artistic

Multicultural

• Saturday, 2025-02-01, 1:00–10:00 p.m., Harris Concert Hall. Lunar New Year Celebration.

Peer

Musical, theatric, sporting, and academic events involving this section’s students are welcome.

Wellness

• Tuesday, 2025-01-28, 12:15–12:50 p.m., GCMoA. Yoga in the Museum.
• Tuesday, 2025-01-28, 4:30–6:30 p.m., BRAC P103 (Multipurpose Dance Studio). Wellness Yoga.
• Tuesday, 2025-01-28, 7:30–9:00 p.m., Harris Concert Hall (aka Harris Gym). Queer Stompede

Misc

• Thursday, 2025-01-30, 4:00–5:00 p.m., Noyce 3821. CS Major Declaration Info Session.
  • Tea beforehand in the CS Commons.

Other good things

These do not earn tokens, but are worth your consideration.

• Saturday, 2025-02-01, 10:00 a.m.–1:00 p.m., Field House. Grinnell Track and Field Invitational.

Upcoming work

• Due Friday, 2024-01-24
  • Read the Web site and answer questions.
  • Tell me about yourself.
• Due Sunday, 2024-01-26
  • Lab writeup from today’s class
  • Read things in preparation for the third day of class.
    • Simple images in Racket
    • Decomposition
    • Writing your own procedures
  • Report on what you’ve read
  • Read the instructions Mini-project 1: Layers
  • Pre-reflections on MP1

Friday PSA

• If you choose to ingest substances that may alter your body chemistry, please do so in moderation.
• What is appropriate for you may be different than what is appropriate for others. Consider in advance what your limits should be.
• Consent is essential.

Q&A

I have answered questions for all the reading responses that came in by 8:00 p.m. If you have another question and want it answered now, please ask.

Administrative

How do I record tokens?

On the “Tokens earned” assignment on Gradescope.

Does Racket have any real-world or industry applications, or is it mainly just designed as a teaching tool?

A variant of Racket was used to both the first version of Yahoo Stores. There are a few niche software development studios that use Racket. But DrRacket is mostly for teaching. Walmart uses Clojure (a more robust Scheme-like language) for sales and inventory management.

Is DrRacket related to DrJava?

Yes.

MathLAN

How do I run Linux on my computer?

You shouldn’t need to run Linux on your computer.

You can run DrRacket on your computer. (Instructions are in the syllabus).

You can also log into MathLAN remotely, but it’s a bit complicated.

https://mathlan.sites.grinnell.edu/fastx/2022/06/08/MathLAN-Remote-Access/.

Racket/Scheme

What is a trivial expression?

One that does not involve any operations. Trival expressions include numbers and strings.

What are values?

The numbers and other things we use in our computations.

What is a basic value?

A value that does not itself contain other values. That may sound werid, but Scheme has things like lists, which contain, well, lists of values.

In the readings, it mentioned that DrRacket and also Scamper had modifications and features designed for beginners. what are these features specifically?

Scamper provides a feature that lets you “trace” how a Scheme expression is evaluated.

DrRacket tries to provide novice-friendly feedback about errors.

Could you clarify what a delimiter is in the string-split procedure?

"Foo,Bar,Baz|Qux,Quux"

The delimiter is the character (or sequence of characters) we use to identify where to split strings. We might split on commas or spaces or ….

What are last set of number inputs when using procedures like outlined-circle?

(outlined-circle 100 "blue" 10)

For an outlined circle, the last set of numbers give the thickness of the outline.

What details are important to keep in mind and not ignore when working with scheme? like order and rules?

Use parentheses to indicate “this is an expression to be evaluated”.

Put the operation immediately after the open parentheses.

Keep track of what kinds parameters (inputs) each procedure has. Do they expect numbers, strings (words surrounded by quotation marks), images, …?

How much time has ellapsed?

25 minutes. I planned fifteen. Whoops.

Debriefing

The pre-instruction activity

How could we have made the putting people in groups process more efficient? (Think, Pair, Share)

Pre-identify locations in the classroom. “All the 4’s go to the appropriate location.”

A leader could ask people with each value to raise their hands.

Show cards in a different way.

The sandwich activity

What might you have learned from the sandwich activity? (TPS)

Be detailed. Be specific.

Don’t expect computers (or others) to have the same world view that we do or to know what we know.

People have different ideas, it can be hard to combine them.

People have different ideas, listen to others’ ideas.

Learn what the recipient of your instructions already knows.

Lab one

• Make sure that both partners attempt the first lab.
• The 2024Sp should be 2025Sp. Sorry!

Lab two

• Jump ahead to 7 a, b, and c
• And then 9
• Turn it in now, even if you didn’t get very far.

Layers!