[[Mach]] is a first-generation [[microkernel]].  Mach's basic abstractions
include [[address_space]]s in the form of [[task]]s, execution contexts in the
form of [[thread]]s, [[IPC]], [[capabilities|capability]] in the form of [[port]]s, and
[[memory_object]]s, which enable Mach's [[external_pager_mechanism]].

Mach's [[API]] is well-[[documented|documentation]].