Editing XNU (section)

===BSD===
The [[Berkeley Software Distribution]] (BSD) part of the kernel provides the Portable Operating System Interface ([[POSIX]]) [[application programming interface]] (API, BSD system calls), the [[Unix]] process model atop Mach tasks, basic security policies, user and group ids, permissions, the network [[protocol stack]] (protocols), the [[virtual file system]] code (including a [[file system]] independent [[journaling file system|journaling]] layer), several local file systems such as [[Hierarchical File System (Apple)|Hierarchical File System]] (HFS, [[HFS Plus]] (HFS+)) and [[Apple File System]] (APFS), the [[Network File System]] (NFS) client and server, cryptographic framework, [[UNIX System V]] [[inter-process communication]] (IPC), audit subsystem, [[mandatory access control]], and some of the locking primitives.<ref>{{cite mailing list|url=http://lists.freebsd.org/pipermail/freebsd-advocacy/2008-August/003674.html|title=Re: freebsd-advocacy Digest, Vol 248, Issue 1|last=Watson|first=Robert|author-link=Robert Watson (computer scientist)|mailing-list=freebsd-advocacy|date=August 2, 2008|access-date=October 24, 2013}}</ref> The BSD code present in XNU has been most recently synchronised with that from the [[FreeBSD]] kernel. Although much of it has been significantly modified, code sharing still occurs between Apple and the FreeBSD Project {{as of|2009|lc=y}}.<ref>{{cite web|url=http://www.freebsd.org/news/status/report-2009-04-2009-09.html#Grand-Central-Dispatch---FreeBSD-port|title=FreeBSD Quarterly Status Report (Grand Central Dispatch – FreeBSD port)|date=April 2009|access-date=October 24, 2013}}</ref>