APIs in the ChorusOS Operating System

The ChorusOS operating system offers three sets of application programming interfaces, including POSIX API compatibility. Each set is intended to serve a certain class of applications.

POSIX Processes

These applications have access to a fully POSIX-compliant API for process management, signals, threads, input/output, memory management, thread sysnchronization, and timing services. This greatly extends the functionality of the ChorusOS operating system, at the same time as allowing easier migration to applications developed by the user, and closer conformity with the Solaris operating environment.

These applications also have access to APIs developed for the ChorusOS services (non existent in POSIX) that conform to the POSIX style, such as system events, black box, watchdog, IPC, and MIPC.

ChorusOS Actors

These include ChorusOS microkernel actors that run the system and the drivers. These applications have access to APIs for all ChorusOS microkernel services.

ChorusOS 4.x Legacy applications

An API developed for release 4.x of the ChorusOS operating system, to support applications developed with POSIX-like functionality without being fully POSIX-compliant. Now superseded by the full POSIX implementation described above, but retained for reasons of backward compatibility.

The POSIX processes and the ChorusOS actors combine to provide a rich range of functionality. However, the two APIs are mutually exclusive. For details of the implementations of these APIs in release 5.0 of the ChorusOS operating system, see API(5FEA).