Compilers (CS 153) – Fall 2021

Module Topic: Free Software: Freedoms and Responsibilities
Module Author: Trystan S. Goetze

Course Level: Lower-level undergraduate
AY: 2021-2022

Course Description: “Implementation of efficient interpreters and compilers for programming languages. Associated algorithms and pragmatic issues. Emphasizes practical applications including those outside of programming languages proper. Also shows relationships to programming-language theory and design. Participants build a working compiler including lexical analysis, parsing, type checking, code generation, and register allocation. Exposure to run-time issues and optimization.”

Semesters Taught: Fall 2021-2022

Tags

• free software (cs)
• open-source software (cs)
• licensing (cs)
• rights and freedoms (phil)
• responsibility (duty) (phil)

Module Overview

In this module, we consider the question of whether the freedoms protected by free or open-source software come with any ethical responsibilities. After an introduction to the history of free software, students learn about the four freedoms protected by free software licenses, such as the GNU General Public License (GPL). We then consider some of the differences between free, open-source, and proprietary software, and why you might choose one licensing scheme over another. We then raise a philosophical question: do freedoms come with responsibilities? In particular, this is framed as an issue of giving back to the community or institution that safeguards those freedoms, so that they can continue to be preserved. Using an analogy with the Tragedy of the Commons, we explore several arguments for and against the idea that users of free or open-source software have an ethical obligation to contribute to those software projects. We also consider whether other institutions, such as big tech corporations or governments, could do the job instead.
Students continue thinking through these issues by discussing a realistic case study that asks them to imagine a dialogue between a software developer and her boss over whether to release a new compiler backend as open-source or to keep it as a trade secret. In the follow-up assignment, students continue to think through these issues by writing a short piece on whether the government should levy a software tax to fund free or open-source projects, or, whether the purpose of a piece of software matters when choosing the licensing scheme one publishes it under.

    Connection to Course Technical Material

The connection to the course material is made in a few places explicitly, but implicit throughout the lesson is that many popular compilers are entirely or partially free or open-source. In addition, the lecture raises the question of whether anyone should be allowed to own something as fundamental to computing infrastructure as a compiler – but, because compilers are dependent on proprietary hardware on the backend, a conclusion that compilers should be free software may quickly become an argument that all software should be free, which is a much more controversial stance. The case study also engages with the course material by imagining a developer who creates a new backend for a compiler to use in creating software for medical devices. One of the assignment questions (on the purpose of the software) may also bring in compilers as one function software may serve that could be relevant in deciding whether to release it as free or open-source.

Goals

    Module Goals

By the end of the module, students will be able to:

1. Understand the origins and motivations of free and open-source software.
2. Know the differences between free, open-source, and proprietary software.
3. Understand the freedoms protected by free software.
4. Be familiar with and critically engage with arguments for and against the notion that the freedoms protected by free or open-source software come with ethical responsibilities to contribute to those projects.

    Key Philosophical Questions

1. Do freedoms come with ethical responsibilities (duties, obligations)?
2. On whom does the responsibility of maintaining shared community resources fall?
3. How do we decide between different value sets, such as the business interests of a company vs. the ethical good the company could do?

Materials

    Key Philosophical Concepts

• Freedoms / Rights Select circle icon with letter ‘i’ to read the marginalia for this paragraph
• Responsibilities / Duties Select circle icon with letter ‘i’ to read the marginalia for this paragraph
• Different domains of values (ethical, business, legal)

    Assigned Readings

• Richard Stallman, The GNU Manifesto
• Optional reading: Trystan Goetze, “An IP Cheat Sheet”

Implementation

    Class Agenda

1. Introduction
2. Origins of Free Software
3. Freedoms of Free Software
4. Distinctions between free, open-source, and proprietary software
5. Do freedoms come with responsibilities?
6. Application to free and open-source software
7. Discussion of the case study
8. Wrap-up and assignment instructions

    Sample Class Activity

Song Li is a senior developer for Physicker, a healthcare technology company. Her boss, Mavis Sloane, has asked Song to use mainly open-source tools so that the company can save on costs. Song selects an open-source compiler that works well with the languages Physicker’s development pipeline prefers.
Song soon finds that some of the hardware used by a few of Physicker’s clients isn’t very well supported by the compiler she chose, and there aren’t good open-source alternatives with a frontend that supports their preferred languages. So, she spends some time developing a new backend for the compiler.
Sloane is impressed, and wants to keep the new backend as a proprietary trade secret. Song, on the other hand, wants to release her work under the same open-source license as the original compiler.

1. What could Song argue when she presents her case to Sloane?
2. What counterarguments might Sloane make in response? How could Song reply?

.

    Module Assignment

In the style of a blog post (250–300 words), write an answer to one of the following prompts:
Option 1: Should the government levy a tax on proprietary software, and distribute the funds to support free and open-source software? Why or why not?
Option 2: Does the purpose of a piece of software (e.g. medical, accounting, software development) matter when considering whether to release it under a free or open-source license? Why or why not?

    Lessons Learned

Students listened attentively to the lecture segment. They were engaged during the discussion, and raised many issues that hadn’t been explicitly discussed in the lecture (e.g. power dynamics between employee and boss, business values vs. ethical values).
I used a website called Padlet to capture their thoughts from the discussion, which was effective in giving us a fall-back resource for continuing the discussion when students were no longer raising their hands. The Padlet was filled with far more notes than we could possibly take up in class.
No one group was unanimous in thinking that the issues in the case study were easy to solve.
Pedagogical insights:

• The students who attended were remarkably engaged. This may be an effect of the course being upper-division.
• Attendance was good, but probably less than 50% of registrants. This may be an effect of class attendance being explicitly optional for the majority of class sessions.
• Students didn’t seem to need/want much time to think individually on the case study before talking in groups.
• Concerns about business values (e.g. profitability, reputation, legal risk) seemed to be well-engrained in the students, and made it sometimes challenging to shift to a focus on ethical values.