Hardware Virtualization

Hardware Virtualization

1. Types

   • Full Virtualization
     • Here, the hardware architecture is completely simulated. Guest software doesn't need any modification to run any applications.
   • Para-Virtualization
     • Here, the hardware is not simulated; instead, the guest software runs its isolated system.
   • Hardware assisted virtualization
     • Here, the virtual machine simulates the hardware & is independent. Furthermore, the guest OS doesn't require any modification.

2. Rings

   • Ring 0
     • Ring 0 is the most privileged layer
   • Ring 1
     • Ring 1 is a bit less privileged
   • Ring 2
     • It is also a bit less privileged ring than RIng 1
   • Ring 3
     • Ring 3 is where the user applications reside with no privileges to manage the hardware resources at all

3. Properies/Features

   • Increased Security
   • Managed Execution
   • Sharing
   • Aggregation
   • Emulation

4. Full vs Para Virtualization

   • Full Virtualization is less secure as compared to para
   • Full Virtualization is more portable and compatible whereas para virtualization is less compatible.
   • Paravirtualization uses hypercalls at compile time for operations while uses binary translation and direct approach as a technique for operations.
   • Examples of Paravirtualization are VMware and Xen and of of full virtualization are Microsoft and Parallels systems.