Explore SerenityOS, an open-source UNIX-like OS with a 90s aesthetic, custom core, and focus on productivity. Learn about its ...

If you're new to the UNIX operating system, especially if you're familiar with Windows, you'll find that the file access control mechanisms might not be exactly what you expect.

But my gut feel for this is that Unix is indeed the world's most successful operating system ever. 900 million concurrent users? I don't think even Windows has managed that.