People sometimes ask which distribution to try if they want to learn how Linux works. Common answers are Gentoo, Arch, or Debian. However, I disagree. Each of these distros teach users their particular brand of Linux. There's only one truly pure Linux, and that is Slackware.

Slackware is the oldest surviving Linux distribution. In its early years, Patrick Volkerdin rolled up a kernel, init, libraries, desktop, and applications to make Linux easier for users. And that's still what he is doing today. He doesn't change anything, he doesn't customize anything. Every component is exactly how the original developers intended. For example, users get a vanilla kernel and default desktop configuration.