CS 201 - Fall 2024.

Welcome to CS 201! 09/06/2024

Video of the day

Crab Canon , A Musical Offering, J.S. Bach. See also: Crab canon, which is like a palindrome.

Logical problem of the day

(define (double v)
   ((if (string? v) string-append +) v v))

What is the result of (double 5) ? (From Racket Guide, Section 2.2)

https://pollev.com/slade You may also download the app to your phone. Use the "slade" poll id.

Top Ten Reasons to Learn Racket!

Number 8: Three reasons: recursion, recursion, recursion.

Canvas Quiz of the Day (need daily password)

Most days, there will be a simple canvas quiz related to the lecture. You need a password to activate the quiz, which I will provide in class. These quizzes will count toward your class participation grade. The quiz is available only during class.

Click for today's quiz.

Note: the collaboration quiz is separate. It coincides with the first homework assignment.

Remote login to the zoo using ssh (secure shell)

If you have a mac, you can open your terminal application and enter the following command at the prompt:

ssh netid@node.zoo.cs.yale.edu

where netid is your netid. You will then be prompted for your netid password and duo authentication. If that all works, you be logged into the zoo in your home directory.

If you have a pc, you can install ssh as an extension to the chrome browser. Go to chrome web store page for ssh and click the "Add to Chrome" button.

You trigger the ssh extension by clicking on the appropriate link on the extensions menu. You then need to configure a connection using the connection dialog link. Here is my connection dialog.

Modify by replacing my netid (sbs5) with yours. When you click enter, you will be prompted for your netid password followed by duo authentication.

Once we have covered a bit of UNIX, I will show you how to automate the duo authenticaion using another encryption method.

You need to be on Yale Secure or VPN to access the zoo. To test, try to contact a zoo machine:

ping lion.zoo.cs.yale.edu

ping utility

Other linux internet commands See

traceroute yale.edu

Lecture 4: Racket / UNIX.

Administrivia

Coursetable - Alex Schapiro

I hope you had a nice summer. I am running CourseTable this year, and I would love to come by 201 this week to tell the class that they can apply to work with us! If that would be possible, please let me know a time that works for me to make a brief announcement.
Alex Schapiro

I am available for lunch on Monday September 9 at noon at Franklin College Dining Hall.

I have office hours Wednesdays from 4-6 pm, on zoom, id 459 434 2854.

ULA office hours are found at https://csofficehours.org/CS201/schedule. Sign up via the queue.

If you're thinking of taking CPSC 201, please do the following.

Complete this online Student Information form.
Get a course account for CPSC 201 on the Zoo. When you register for this class, your course account should be created within one hour or so of signing up.
Homework assignments: [Assignments]. hw0.rkt revised to define runtests to make the autograder happy. Plus, the autograder wants hours to be an integer. If you lost a point on hours, resubmit with an integer. Also, hw1 is now available.
Familiarize yourself with the Zoo computers using the above instructions for ssh. We will start discussing UNIX soon.
(Optional.) Download and install DrRacket on your computer (Racket) and familiarize yourself with it (Choose language: "Use the language declared in the source", #lang racket. Then press the Run button to actually change the language.) If you don't want to install and run DrRacket on your machine, you may run it in person or remotely using your Zoo account.

Racket.

Racket.html (jupyter) lambda

Getting to know UNIX

UNIX Introduction

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