We can see from the development of the various architectural models that an actualization of the operating system goals was paramount as research was carried out.
The layered structure addresses the cumbersomeness of coding associated with the monolithic architecture while the microkernel framework with an improved degree of modularity reduces the infringement of boundary protection associated with the layered architecture thereby providing high level of extensibility, scalability, security, portability, robustness, efficiency and usability of a microkernel based operating system.
Further, in recent times as operating systems are been developed, the expectations of operating system’s portability, extensibility, security, scalability and robustness are been considered to ensure a usability of the operating system through an hybrid kernel design using the various architectural models {[5].