What is Virtualization?

Virtualization is a word that includes different technological innovation.  Virtualization is generally described as the capability to run more than one Program or OS on a single and actual physical program or it can be define as Virtualization is a term that refers to the various techniques, methods or approaches of creating a virtual (rather than actual) version of something.  We need to determine virtualization and the conditions associated with it. Second there are three significant groups of virtualization, I am going to determine them as:

  1. Hypervisor Virtualization or Type-I Virtualization
  2. Hosted Virtualization or Type-II Virtualization
  3. Application Virtualization

Hypervisor Virtualization or Type-I Virtualization

This kind of hypervisor is implemented as a bare-metal set up. This implies that the first thing to be set up on a physical server as the OS will be the hypervisor. The advantage of this application is that the hypervisor will connect straight with the actual hardware components. Those sources are then paravirtualized and sent to the operating VMs.  Each VM appears to have the host’s processor, memory, and other resources all to itself. However, the hypervisor is actually controlling the host processor and resources, allocating what is needed to each operating system.  It also keeps the sources for exclusive devices separate and protected.

hypervisorapproach

This scenario has been adopted by large industries and key enabler of cloud computing and cloud infrastructure.  It also enables dynamically provisionable infrastructures like servers, storages and application hosting, while making it much simpler to manage.

Advantage Disadvantages
Better control on hardware More Costly
Centralized management Difficult to manage
Maximum uptime of VMs

Software Example

VMWare ESX(vSphere) Server, Citrix Xen Server, Microsoft Hyper-V

Hosted Virtualization or Type-II Virtualization

This is the easiest kind of virtualization to set up for newbie level or for testing purposes. This is often the place to start for most IT companies looking to get into virtualization on an extensive level. Hosted virtualization exists on top of a different OS like Windows, Linux and Unix Systems.  In this environment all Input/Output is dependent on the host OS.

hostbasedhypervisor

In this scenario as you can see if there is maintenance program for hardware or operating system, virtual instances required to be down.  So it is good for small scale and deployment situations and normally used in desktop pc and laptop environments.

Advantage Disadvantages
Low Cost No failover/Redundant
Easy to manage No centralized management
Free Hypervisor Software

Software Examples

VMWare Workstations, VMWare Fusion, Virtualbox, Microsoft Virtual PC

Application Virtualization

Application virtualization is a technological innovation that encapsulates application from the actual OS on which it is implemented. Application virtualization have advantages from central control.  Programs can be set up, repaired, and improved once as a whole atmosphere, instead of for each personal computer.

applicationvirtualization

These virtual applications can be placed in a sealed sandbox where they do not have the capability to impact the actual OS elements straight.  This can be incredibly useful for operating several inconsistent editions of the same application on the same program. This is also a way to avoid applications from damaging a fresh OS picture on a customer laptop or computer or hosting server

Advantage Disadvantages
Better control Difficult/Complexity
Security through sandboxing Cost
Multi platform application support

Software Examples

VMWare Thinapp, Citrix Xenapp, Microsoft Application Virtualization (vApp)

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