1. Test Optimization Using Software Virtualization
Frank Pacelli

2. Agenda Problem illustration Virtualization defined
4 virtualization approaches
Virtualized test platforms
Virtualization product options
Other options

4. What is Virtualization?
Multiple OS or "Virtual Machines" installed on one physical machine.
VMs run in parallel to one another
VMs don't realized they are virtualized
Each VM is isolated from the others
The host simulates a hardware environment for each VM
'Guest' OS may vary in type
Limited only by hardware
The host may be an OS, special hardware, or special software

5. Virtualization Approaches
Full system virtualization
Paravirtualization
Native virtualization
OS level virtualization

6. Full-System Virtualization
Virtualization is transparent to virtual machine
Sophisticated software simulates hardware
3 levels above hardware

7. Paravirtualization Underlying virtualization software exposes API
'Guest' OS must be modified significantly to use this API instead of actual hardware
3 levels above hardware
In other words, virtualization is not transparent to guest OS.

8. Native Virtualization
Virtualization is transparent to virtual machine
Hardware handles routing of instructions to/from virtual machine
1 level above hardware

9. OS-level Virtualization
Only 1 OS actually installed
OS is capable of partitioning itself so it looks as if there are multiple instances
1 level above hardware

10. Virtualized Test Platforms
Virtualization can be used in countless configurations to optimized testing
Host OS is irrelevent

17. Virtualization Products
Emulation - simulates hardware that doesn't exist on that physical machine. Simulate a 486 processor on a non 486.
Hypervisor - virtual machine monitor. Can be installed on top of hardware, or on top of host OS.
Full system simulation - similar to emulation except that the exact behavior of the hardware is mimiced, not just the minimum to make the software run.

18. Other Options Simulation Attempt to model real behavior/data
Can only be used for unit testing
Partially real test setup
hybrid approach
partial real hardware/software 
partial simulators
partial stubs

19. Summary
Virtualization is multiple OS sharing the resources of one machine
4 approaches
Full system virtualization
Paravirtualization
Native virtualization
OS level virtualization
Many different configurations can be used to create the optimum test environment
Open source and commercial solutions available
Virtualizatiion reduces costs, energy consumption, testing complexity, and required rack space

20. References
Swaminathan Seetharaman, Krishna Murthy B.V.S., "Test Optimization Using Software Virtualization" IEEE Software. Sep/Oct, Page(s) 66-69