Modularity and protection should be decoupled

It is argued that a modular operating system architecture should provide support for modularity that is independent of protection domains. Given such support, modules and interfaces can be designed according to sound software engineering principles, without concern for cross-domain invocation costs. The partitioning of modules into domains (and across machines) becomes a matter of configuration, rather than design. Current microkernel-based architectures do not sufficiently address this issue since their communication mechanisms are designed for the nonlocal, i.e., cross-domain case. An architecture is proposed that provides location-transparent binding and access of modules optimized for the local case, thereby decoupling modularity and protection