Microkernel Approach
The organizing structure currently in vogue is the microkernel OS.
Goal is minimize what goes in the kernel, and implement much of the OS as user-level processes. This results in:
- better reliability
- ease of extension and customization
- mediocre performance (unfortunately)
First microkernel system was Hydra (CMU, 1970)
Examples of microkernel systems are the CMU Mach system, Chorus (French Unix-like system), and in some ways Microsoft NT/Windows.