Topics Technology and the internet

What is open-source software?

Open-source software is software whose source code, the human-readable instructions written by programmers, is published so anyone can read it, run it, change it and share it, under a license that spells out the terms. The license is the key part. Code that is merely visible is not necessarily open source; the permission to reuse and modify it is what counts.

What makes it interesting is how much of the modern world quietly runs on it. Much of the web's server software, the Linux operating system, the Android phone platform's core, and many programming languages and tools are open source. Strangers, companies and volunteers often work on the same code, and the license decides what happens next. Some licenses are permissive and let you do almost anything. Others, called copyleft, require that if you pass on a modified version, you share your changes under the same terms.

An episode would walk through where the idea came from, how the licenses differ, how projects are actually run, and why companies give away code they spent money to write. It would also cover the real downsides, like overworked volunteers and security bugs. bre's hosts are AI, so they can be wrong, and the episode says so.

What a bre episode would cover

An outline of the episode bre would make for this question. Every episode is written fresh when you ask, so yours will differ.

  1. Source code, explained plainlyWhat source code is, how it differs from the finished app on your phone, and why seeing the recipe matters.
  2. The license is the whole pointWhy public code is not automatically open source, and how a license grants permission to use, change and share.
  3. Permissive versus copyleftSome licenses allow nearly any reuse, while copyleft licenses require shared changes to stay open. We look at why people choose each.
  4. How a project actually runsMaintainers, contributors, and the review process that decides which changes make it into the official version.
  5. Why companies give code awayShared maintenance, trust, hiring and standards are some reasons. Motives vary, and we say which are debated.
  6. Open source and securityMany eyes can catch bugs, but only if someone is really looking. Open code is not automatically safe.
  7. Free as in speech, free as in beerThe difference between freedom to use code and a price of zero, and how some open projects still earn money.

How the episode might open

A sample exchange between two of bre’s AI hosts, bre and Cal. Both are AI; this is written by AI, as every bre episode is.

  1. breAI host

    Let's start with a picture. You've got a cake you love, and you can only buy slices. Closed software is that. Open source is the baker handing you the recipe and saying, go ahead, change it.

  2. CalAI host

    Okay, I like that. Although a recipe on a billboard isn't the same as a recipe you're allowed to use. Right? Somebody's got to say what you're permitted to do with it, or you're just guessing.

  3. breAI host

    Exactly, and that's the part people skip. The permission slip is the license. Without it, public code can still be off limits to copy or sell.

  4. CalAI host

    Hold on, how does that actually work? Like, if I change the code and hand it to a friend, who decides whether I broke a rule? There's no referee standing there.

  5. breAI host

    The license is the referee, and ultimately courts if it comes to that. Some licenses say do what you like. Others say, if you share yours, you share the changes too.

  6. CalAI host

    So that's two very different philosophies hiding under one label. That's money, control, who wins. I want to know why anyone would pick the strict one.

  7. breAI host

    Good question, and honestly people still argue about it. We'll get there. First, what's actually in a piece of source code, and why can't you just read the app you already have?

Questions people also ask

Is open-source software free?
Often it costs nothing to download, but free of charge is not the definition. Open source means you have the code and permission to use, change and share it. Some projects and companies sell support, hosting or packaged versions. Free software without public code is not open source.
Can anyone change open-source software?
Anyone can usually copy the code and change their own version. Changing the official project is different: maintainers review and decide what to accept. Some licenses also require you to share your changes if you pass the software on, while permissive ones do not.
What are some examples of open-source software?
Well-known examples include the Linux operating system, the Firefox browser, the Python programming language, and the Apache web server. Android is built on open-source parts, though phones add other software on top. Many apps and tools you use contain open-source pieces without saying so.
Is open-source software safe?
It can be, but it is not automatically safe. Public code lets many people inspect it and report flaws, which helps. But a project that few people review, or that is poorly maintained, can still hide serious bugs. Safety depends on the project and how well it is looked after.

Related topics

More: all 300 topics, technology and the internet, or the longer reads on /learn.

bre’s hosts are AI, and every episode is generated, so they can be wrong: check anything that matters. This page outlines what an episode would cover. It is for interest and learning, not medical, financial or legal advice.