Hardware Virtualization

Hardware Virtualization

1. Definition: Server virtualization (also referred as hardware virtualization) is the best known application for hardware virtualization today. Today’s powerful x86 computer hardware was designed to run a single operating system and a single application. This leaves most machines vastly underutilized. Virtualization lets you run multiple virtual machines on a single physical machine, sharing the resources of that single computer across multiple environments.

2. PROTECTION RINGS

   • RING 0: MOST PRIVELEGED
   • RING 1: THIS IS WHERE DEVICE DRIVERS EXECUTE
   • RING 2: HERE ALSO DEVICE DRIVER EXECUTE
   • RING 3: LEAST TRUSTED HERE APPLICATIONS RUN

3. PROPERTIES

   • PARTITIONING: Run multiple operating systems on one physical machine. ■ Divide the physical system resources among virtual machines. ■ One VM does not know the presence of the other.
   • Management ■ Failure of one VM does not affect other VMs. ■ Management agents can be run on each VM separately to determine the individual performance of the VM and the applications that are running on the
   • Encapsulation ■ The entire VM state can be saved in a file. ■ Moving and copying VM information is as easy as copying files.
   • Flexibility ■ Allows provisioning and migration of any VM to a similar machine on any physical server. ■ Usage of multiple OS platforms, for example, Windows, Linux. ■ Allows VM configuration changes without actually bringing the VM down

4. FULL VIRTUALIZATION : Full virtualization is a virtualization technique used to provide a VME that completely simulates the underlying hardware. In this type of environment, any software capable of execution on the physical hardware can be run in the VM, and any OS supported by the underlying hardware can be run in each individual VM.

5. PARA VIRTUALIZATION: Paravirtualization is the category of CPU virtualization which uses hypercalls for operations to handle instructions at compile time. In paravirtualization, guest OS is not completely isolated but it is partially isolated by the virtual machine from the virtualization layer and hardware. VMware and Xen are some examples of paravirtualization.

6. 19BCE1559

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