1. CS533 Concepts of Operating Systems Class 15 Virtualization

2. CS533 - Concepts of Operating Systems 2 Questions  At what granularity do VM monitors support multitasking? o How does it differ from conventional multitasking? o How do virtualized CPUs differ from threads/processes?  Does virtualization hide any critical characteristics of the real hardware?  Why is it difficult to virtualize the x86?  What hardware support would be nice to have?

3. CS533 - Concepts of Operating Systems 3 Questions  What is the difference between … o full virtualization and para virtualization? o virtualizing and multiplexing resources?  Are Disco and Xen micro-kernels? o Do they support modularization of operating system code? o Do micro-kernels do virtualization? o Does Xen use colocation?  How do VM monitors/hypervisors ensure safety? o Is virtualization a sandboxing technique?

4. CS533 - Concepts of Operating Systems 4 Questions  Why would a guest OS need real, virtual and wall clock time abstractions?  Why would a guest OS need machine addresses instead of just virtual physical addresses?  What kind of virtualization is needed for binary compatibility?  Why isn’t an emulation library approach equivalent to a virtual machine approach?

5. CS533 - Concepts of Operating Systems 5 Questions  Why is para-virtualization needed for high performance on architectures such as x86?  Why is it harder to virtualize CPUs with hardware specified page tables than software managed TLBs? o Why do tagged TLBs help?  Xen is not transparent to a guest OS. In what ways can the OS distinguish execution on Xen from execution on bare hardware?

6. CS533 - Concepts of Operating Systems 6 For more information …  do a google search on Xen, VMWare, and Vanderpool or VT.