Virtualization

❖ Virtualization:

Virtualization is a technique, which allows to share single physical instance of an application or resource among multiple organizations or tenants (customers).

It does so by assigning a logical name to a physical resource and providing a pointer to that physical resource when demanded [3]. Her we have three types of hardware virtualization:

1. Full Virtualization 
2. Emulation Virtualization 
3. Paravirtualization.

Creating a virtual machine over existing operating system and hardware is referred as Hardware Virtualization. Virtual Machines provide an environment that is logically separated from the underlying hardware.

 The machine on which the virtual machine is created is known as host machine and virtual machine is referred as a guest machine. This virtual machine is managed by a software or firmware, which is known as hypervisor.

There are two types of hypervisor:

• Type-1 hypervisor: 

Type-1 hypervisor does not have any host operating system because they are installed on a bare system. LynxSecure, RTS Hypervisor, Oracle VM, Sun xVM Server, VirtualLogic VLX are examples of Type 1 hypervisor.

• Type-2 hypervisor: 

Type 2 hypervisor is a software interface that emulates the devices with which a system normally interacts. Containers, KVM, Microsoft Hyper V, VMWare Fusion, Virtual Server 2005 R2, Windows Virtual PC and VMWare workstation 6.0 are examples of Type 2 hypervisor.