1. CS533 Concepts of Operating Systems Class 13
Micro-kernels (or Extensibility via Hardware-Based Protection)

2. CS533 - Concepts of Operating Systems
Questions
What is the structure of a pure emulation library-based OS above a micro-kernel?
How are system calls handled?
What is the structure of a single-server based OS above a micro-kernel?
What is the structure of a multi-server based OS above a micro-kernel?
CS533 - Concepts of Operating Systems

3. CS533 - Concepts of Operating Systems
Questions
What are the main sources of overhead in micro-kernel based OSs compared to monolithic OSs?
How does L3 address these overheads?
Do these optimizations completely solve the problem?
What is the difference between L4 IPC and a protected control transfer (PCT)?
Would you expect a lot of difference in performance following extreme optimization of both?
What minimal abstractions should a kernel provide?
CS533 - Concepts of Operating Systems

4. CS533 - Concepts of Operating Systems
Questions
What is the motivation for modular operating systems?
Does this imply modules with hardware protection?
.. and what do I mean by hardware protection for modules?
What is the motivation for using hardware protection at module boundaries?
Does this imply message passing across module boundaries?
… what other alternatives do you have?
What is the motivation for using message-passing for inter-module communication?
CS533 - Concepts of Operating Systems

5. CS533 - Concepts of Operating Systems
Questions
What is extensibility and how does micro-kernel-based OS structure help?
What other approaches are there?
CS533 - Concepts of Operating Systems