He was one of the principal architects of the Berkeley 2BSD, 4.4BSD and 4.4BSD-Lite releases. Among many other tasks, he led the effort at CSRG to create a free software version of BSD Unix, which, in turn, enabled the creation of FreeBSD, NetBSD, and OpenBSD.

Bostic was a founder of Berkeley Software Design Inc. (BSDi), which produced BSD/OS,