Index: metadata_posix1e_acls.wiki
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--- metadata_posix1e_acls.wiki	(revision 0)
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+#summary POSIX.1e ACLs
+= POSIX.1e ACLs =
+
+IEEE POSIX.1e draft proposal ACL API implementation.
+
+== Implementation status ==
+
+Implemented.
+
+== Notes ==
+
+ * Archival of ACLs on Mac OS X 10.4 is currently not possible due to broken ACL implementation. See [http://code.google.com/p/xar/issues/detail?id=5 this issue] for details.
Index: metadata_darwin_ea.wiki
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--- metadata_darwin_ea.wiki	(revision 0)
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+#summary Darwin/Mac OS X Extended Attributes
+= Darwin/Mac OS X Extended Attributes =
+
+Apple's Mac OS X has supported arbitrary metadata since its [http://en.wikipedia.org/wiki/Mac_OS_X_v10.4 10.4 version]. [http://en.wikipedia.org/wiki/Extended_file_attributes#Mac_OS_X Wikipedia section on Mac OS X ACLs].
+
+== Implementation status ==
+
+Implemented.
Index: metadata_bsd_ea.wiki
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--- metadata_bsd_ea.wiki	(revision 0)
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+#summary BSD Extended Attributes
+= BSD Extended Attributes =
+
+FreeBSD-style Extended Attributes. The [http://en.wikipedia.org/wiki/Extended_file_attributes#FreeBSD Wikipedia ACLs entry on FreeBSD ACLs] has a good overview.
+
+== Implementation status ==
+
+Implemented.
+
+== Notes ==
+
+  * Attempting to read the system namespace while not a privileged user is expected to return an error. The system namespace is used, among other things, for storing kernel extended attributes such as ACLs.