In 1986, Bostic joined the Computer Systems Research Group (CSRG) at the University of California, Berkeley.[2] He was one of the principal architects of the Berkeley 2BSD, 4.4BSD and 4.4BSD-Lite releases.[3] Among many other tasks, he led the effort at CSRG to create a free software version of BSD UNIX, which helped allow the creation of FreeBSD, NetBSD and OpenBSD.