@dorentus It is based on U.C. Berkeley's “4.4BSD-Lite” release, with some “4.4BSD-Lite2” enhancements. It is also based indirectly on William Jolitz's port of U.C. Berkeley's “Net/2” to the i386™, known as “386BSD”, though very little of the 386BSD code remains. freeBSD 官网上抄下来的 Mach没记错的话是CMU搞出来的。。。