The kernel vs the OS
"Linux" strictly refers to the kernel — the program managing hardware, processes, memory, and I/O. A distro pairs it with GNU utilities and a package manager. Ubuntu, Debian, Fedora, and Alpine are major distributions.
How Linus Torvalds started it
In August 1991, Finnish CS student Linus Torvalds announced a free OS kernel just for fun. By v1.0 in 1994, Linux had a global community. Today it has thousands of corporate contributors.
Why Linux won the server
Linux is free, auditable, deeply customisable, and runs from Raspberry Pi to the world's fastest supercomputers. Every major cloud provider runs Linux. The reliability, performance, and cost advantages are decisive.
Linux and Android
Android, running on 3 billion+ devices, is built on the Linux kernel with Google modifications. Every Android phone runs Linux.
The open-source model
Licensed under GPL v2: anyone may study, modify, and redistribute it if they share modifications under the same licence. This drove unprecedented global collaboration.
