CS533 Concepts of Operating Systems

Class 12

Extensibility via Software Based Protection

CS533 - Concepts of Operating Systems 2

Questions

What is extensibility and how does micro-kernel-based OS structure help?

o What other approaches are there?

CS533 - Concepts of Operating Systems 3

Questions

Why does Sandboxing slow down normal execution?

Why does it speed up inter-module communication compared to Mach?

What is a jump-table and why is it needed? On balance is Sandboxing a win or loss?

o compared to Mach?o compared to L3/L4?

CS533 - Concepts of Operating Systems 4

Questions

What exactly is a protection domain in SPIN? How are module boundaries implemented in

SPIN?o What implications does this have for kernel extensions?

How does extension code invoke SPIN’s core services, or code in other modules?

How do SPIN’s core services compare to those of micro-kernels?

CS533 - Concepts of Operating Systems 5

Questions

Does the SPIN approach slow down normal execution?

How does it speed up inter-module communication?

On balance is it a win or loss?o compared to Mach?o compared to L3/L4?o compared to Sandboxing?