PUBLIC MARKS from xenomorph with tags documentation & networking

Darwin is the open source UNIX-based foundation of Mac OS X. Darwin integrates a number of technologies. Among the most important are the Mach 3.0 microkernel operating-system services, based on 4.4BSD (Berkeley Software Distribution), the high-performance networking facilities, and the support for multiple integrated file systems. Darwin also includes a number of command-line tools. Mac OS X developers can use Darwin to port UNIX/Linux applications and to create kernel extensions.