BSD

The Berkeley Software Distribution (BSD), also known as Berkeley UNIX, is a Unix operating system developed and distributed by the Computer Systems Research Group at the University of California, Berkeley. First released in 1978, it began as an improved derivative of AT&T's original Unix developed at Bell Labs, based on the source code. Over time, BSD evolved into a distinct operating system and played a significant role in computing and the development and dissemination of Unix-like systems.