Software by licence and purpose¶

Exercise software-by-licence-and-purpose-annex.pdf · PDF

Since September you have installed dozens of programs: Debian, Windows 11, Git, Samba, LibreOffice, WinBox... Quick question: which of them are you allowed to copy for a friend? Which can you change? And which ones are you only renting? If your answer is "the ones I didn't pay for are free", this page is for you.

Yesterday you handed over the Tramuntana office server. A server nobody understands is a server nobody can repair, so Unit 7 has one product: a documentation repository for that server — text files, kept under version control, that build a PDF. Today you write one piece of it: the table of software it runs, each line with its licence. And every answer comes with proof.

Back to October: the four freedoms¶

You met licences in Unit 2 — the full story is on Software licences. Here is the short version you need today.

A licence is the document that says what you may do with a program: run it, copy it, change it, share it.

Free software gives you four freedoms, numbered from 0 (programmers count from zero):

Freedoms 1 and 3 need the source code — the human-readable text the program was written in. Without it, "change it" is just a promise on paper.

Free licences come in two flavours:

• Copyleft (GPL): you may change it, but a version you share must keep the same licence. Freedom is contagious.
• Permissive (MIT, Apache 2.0): almost no conditions. Your changed version may even become closed.

Two axes, not one¶

Every program has a place on two axes, and they do not depend on each other. Knowing one tells you nothing about the other.

Axis 1: purpose — what is it for?¶

Axis 2: licence — what may you do with it?¶

Put both axes together and you get a grid. Git lands in development · copyleft. WinBox lands in system utility · freeware. Windows 11 lands in system · proprietary, paid.

flowchart LR
    P["<b>A program</b>"] --> Q1{"<b>Purpose?</b><br>what is it for"}
    P --> Q2{"<b>Licence?</b><br>what may I do"}
    Q1 --> S["System"]
    Q1 --> A["Application"]
    Q1 --> D["Development"]
    Q2 --> C["Copyleft"]
    Q2 --> PE["Permissive"]
    Q2 --> PP["Proprietary, paid"]
    Q2 --> F["Freeware"]

Four words that get mixed up¶

Open source¶

Open source is software whose licence meets the Open Source Initiative's definition: you may use, study, change and share it.

The name was proposed in February 1998 by Christine Peterson; the Open Source Initiative keeps a definition with 10 criteria. The older name, free software, comes from the GNU project (announced in 1983) and the Free Software Foundation (founded in 1985). Two names, two motivations, but in practice one list of licences and nearly the same programs.

Source-available¶

Source-available software lets you read the code, but its licence restricts what you do with it.

Reading is not enough to be open source. A true story: on 10 August 2023 the company HashiCorp moved its tool Terraform from an open source licence (MPL 2.0) to the Business Source License, whose own text says it is not an open source licence. Within six weeks the community announced a fork — a copy of the project that continues on its own — called OpenTofu, under the Linux Foundation.

The lesson: the owner can change the licence of the next version. The versions already published keep the licence they had. That is exactly why the fork was legal.

SaaS¶

SaaS (Software as a Service) means you install nothing: the program runs on the provider's computers and you use it through a browser or an app.

You rent access, usually per user per month. Google Docs and Figma are SaaS.

No licence¶

A project on the Internet with no licence file is not public. By default the author keeps exclusive copyright: nobody else may copy, change or share it. You may only look.

Proof, not opinion¶

A label without proof is a guess. Here is where the proof lives.

For anything installed with apt on deb-lab, every Debian package ships a copyright file:

less /usr/share/doc/git/copyright
grep -m1 "^License:" /usr/share/doc/git/copyright

On Debian 13 the second command prints:

License: GPL-2

Git is under the GPL version 2: copyleft. Try the same with bash and you get GPL-3+ (version 3 or any later one).

For programs that are not Debian packages, the proof is the licence page on the project's own website, or the LICENSE file in its repository. A blog post is not proof.

Here is how the software of this course classifies, with the proof for each line:

The purpose axis has fuzzy borders: Podman could be system or development, an editor could be application or development — defend your choice. The licence axis has no fuzzy borders: the file says what it says.

The hard cases¶

VS Code: one code, two faces¶

The source code of Visual Studio Code is open, under MIT. But the installer most people download is a Microsoft product under a proprietary licence. VSCodium is that same source built and distributed under MIT. So "open source" describes the licence of a specific thing you have in your hands, not a brand.

RouterOS: proprietary on top of free¶

RouterOS runs on a Linux kernel, and the product is proprietary. That is allowed: a proprietary product can be built on top of free software as long as it respects the licences of the parts.

Your documentation needs a licence too¶

The repository you start next week is a creative work. With no licence, nobody may reuse it. Software licences (GPL, MIT) are written for code. For text, the usual choice is a Creative Commons licence, for example CC BY-SA 4.0: anyone may share and adapt it, as long as they name the author and keep the same licence. Creative Commons itself recommends against using its licences for software.

You will add a LICENSE file to your repository. Decide which one before the Docs as code session.

Key takeaways¶

• Every program sits on two independent axes: purpose (system, application, development) and licence (copyleft, permissive, proprietary paid, freeware).
• Free software is about freedom, not price: freeware costs nothing and is still proprietary.
• Open source means you may use, study, change and share; source-available only lets you read.
• SaaS says where software runs and how you pay — the licence is a separate question.
• No licence means exclusive copyright: you may only look.
• A classification needs proof: /usr/share/doc/<package>/copyright or the project's own licence page.

Quick check¶

Now that you can label software, the next step is choosing it — for a studio, a school and a hotel, and counting what it really costs: Software needs in real workplaces.