 FreeBSD 's roots go back to the University of California , Berkeley . The university acquired a UNIX source license from AT & T. Students of the university started to modify and improve the AT & T Unix and called this modified version Berkeley Unix or BSD , implementing features such as TCP / IP , virtual memory and the Unix File System . The BSD project was founded in 1976 by Bill Joy . But since BSD contained code from AT & T Unix , all recipients had to get a license from AT & T first in order to use BSD . 
