Z:gnu-www-ja-linux-and-gnu--ed5a11-Addendum: Aside from GNU, one/en

Addendum: Aside from GNU, one other project has independently produced a free Unix-like operating system. This system is known as BSD, and it was developed at UC Berkeley. It was non-free in the 80s, but became free in the early 90s. A free operating system that exists today(4) is almost certainly either a variant of the GNU system, or a kind of BSD system.