How modularity relates to security

The routines within each service subsystem must exhibit software modularity. Modularity means that, within each of the seven service areas defined by the system architecture, the routines are grouped into independent, distinct modules, each of which

• has a single, well-defined function

• has well-defined interfaces

• has well-defined parameters

• is called whenever its function is required

Modularity within the system architecture enforces security by keeping operating system functions separate and unique. Thus, modular system architecture is a requirement of the security policy for UnixWare.