API Reorganization and POSIX Compliance

The APIs in version 5.0 of the ChorusOS operating system have been reorganized to support three kinds of applications:

POSIX processes

Most of the applications running on ChorusOS systems will be POSIX processes. These applications have access to the pure POSIX APIs, a few POSIX-like extended APIs and a small number of restricted microkernel system calls.

ChorusOS actors

These applications are run on top of the microkernel and restricted to the microkernel API. ChorusOS actors include drivers, subsystem events and protocol stacks.

ChorusOS 4.x Legacy applications

These applications are supported purely for backward compatibility and use the same APIs they used in previous versions of the ChorusOS system. While these applications are supported in ChorusOS 5.0, you are encouraged to move such applications to the POSIX level, using the standard POSIX APIs.

For more information on the reorganization of the APIs, refer to "Introduction to ChorusOS Applications" in the ChorusOS 5.0 Application Developer's Guide and to the API(5FEA) man page.