The Two FreeBSD Source Trees
With Windows and Macintosh, you generally only have one choice for updating your system. You simply go to the store and purchase the new upgrade to Windows or MacOS and then install it on top of the existing version. (Or in some cases, you download a patch from the Internet or use an automatic update program such as that included with more recent versions of Windows.)
With FreeBSD however, you always have to upgrade options available to you. One of the options is called STABLE and the other option is called CURRENT.
What Is a Source Tree?
A source tree is the set of source code files that make up the operating system. Source code files are just plain text files that contain the programming code written by the FreeBSD ...