ChorusOS Actors

An actor is the unit of encapsulation of resources with regard to the ChorusOS microkernel.

Actors are linked only with the microkernel libraries and are completely unknown to the C_OS. A process can load or run a microkernel actor dynamically using the POSIX-like afexec() microkernel service.

For more information on loading actors, see "Spawning an Actor".

An actor can be embedded, which means that it becomes part of the system image. However, actors are not necessarily embedded and can be located on a separate disk or file system. Embedded actors can be bootable, which means that they are executed as the ChorusOS system is booted. Embedded actors that are not boot actors can be loaded by other embedded actors using the afexec() system call.

Actors cannot access POSIX services. If microkernel services and POSIX services are used together in the same application, the behaviour of the application is unpredictable and can even cause the system to crash.

An actor is represented by its capability (KnCap), which is allocated by the microkernel.

Typically, drivers are embedded actors, however drivers do not require the services of the POSIX subsystem and can be started dynamically through the afexec() system call.