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Map · The microkernel core

Mach

Tasks, threads, ports, messages, and the virtual-memory primitives every other layer is built on top of.

apple-oss-distributions/xnuosfmk/kern/task.cStart reading the kernel source here.View on GitHub(line —)
Mach tasks, threads, and port rightsTwo tasks, each owning threads and a port-right table. Both hold send rights to a single port whose receive right and queue live in the kernel.Task Avm_map · ipc_spacethread 1thread 2PORT RIGHTS0x103send0x207recv0x301send-onceTask Bvm_map · ipc_spacethread 1PORT RIGHTS0x901send0xA12recvKernelipc_portmessage queueFIFO of mach_msgmsg #1msg #2sendsendBoth tasks can send. Only one task (the receiver) dequeues.The name 0x103 in Task A and 0x901 in Task B point at the same port.