[[Mach]] is a first-generation [[microkernel]].  Mach's basic abstractions include
[[AddressSpace]]s in the form of [[Mach/Task]]s, execution contexts in the
form of threads, [[Mach/IPC]], [[capabilities]] in the form of
[[Mach/Ports]], and [[Mach/MemoryObjects]], which enable
[[Mach/ExternalPagerMechanism|Mach]].