FreeBSD divides itself into the base operating system and ports. The base OS contains core components while ports contain additional software. There are two ways to upgrade each - through binary packages or by compiling from source. Ports can be installed individually and have no hierarchy, but allow differentiation from the base OS and fine-grained control. The document describes a case study where multiple FreeBSD servers were used together for development, testing, and production in a synchronized way through a build master and CVSup server.