1. CS533 Concepts of Operating Systems Class 15
Virtualization

2. CS533 - Concepts of Operating Systems
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 application binary compatibility?
Why isn’t an emulation library approach equivalent to a virtual machine approach?
CS533 - Concepts of Operating Systems

3. CS533 - Concepts of Operating Systems
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?
Why do tagged TLBs help?
Why use buffer-descriptor rings as an abstraction for device I/O?
Xen is not transparent to a guest OS. In what ways can the OS distinguish execution on Xen from execution on bare hardware?
CS533 - Concepts of Operating Systems

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

5. CS533 - Concepts of Operating Systems
Questions
At what granularity do VM monitors support multitasking?
How does it differ from conventional multitasking?
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 aspect of the x86 helps virtualization?
What hardware support would be nice to have?
CS533 - Concepts of Operating Systems

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