a-kernel

Was a project to determine if AOP can be used to improve OS modularity, and thereby reduce complexity and fragility associated with system implementation.

From its home page:

OS code is notoriously complex, with many systems having millions of lines of code containing subtle and intricate interactions. The inability for programmers to effectively reason about parts of the system, develop components independently, and even configure customized systems at build time are well known ramifications of the deep structural flaws in OS code. The goal of the a-kernel project is to determine if AOP can be used to improve OS modularity, and thereby reduce complexity and fragility associated with system implementation.