Virtualization and Related Concepts

Virtualization, with the word meaning itself, says -- turning things into a virtualized form. Which means a form in which the subject is not physically available but can be used as it were available.

Virtualization in computing terms, is the creation of something in a virtual form rather than in actual, such as a virtual server or virtual storage or a virtual network resource etc...

Virtualization can be of different types like :

• Hardware Virtualization
• Desktop Virtualization
• Mobile Virtualization 
• Other types

Hardware Virtualization again can be divided into different types, as follows:

• Full virtualization - Complete simulation of an actual hardware to allow software, which can have different operating system, to run the application unmodified.
• Partial virtualization - Not all of the environment is simulated, So some programs may require modification to run in this virtual environment.
• Para-virtualization - Hardware environment is not virtualized, but applications can be executed in their own isolated domains, as if they are running on a seperate system. This needs application to be specifically modified to run  on  this environment.

The overall effeciency of virtualization can be improved by using Hardware-Assisted Virtualization.. It involves hardware components and CPUs that provide support for virtualization in hardware., whcih help improve performance of the guest environment.

Desktop Virtualization on the other hand is the concept of seperating physical machine into a logical desktop. It can also be divided into several types, like:

• Virtual Desktop Infrastructure (VDI) - It can be thought of a more advanced form of hardware virtualization. Here the user interacts with the host computer using another device like a PC or hand held using network connection (LAN, WAN etc..), instead of directly interacting with host computer via a keyboard, mouse & monitor etc..
• Session Virtualization - Using single PC with multiple sessions created to allow multiple users to connect and login to a shared server / PC over the network, and use it simultaneously. In this each user will be provided with a personal folder for storing their data/files.
• Thin Clients - These are simple and cheap computers used for desktop virtualization, and are primarily designed to connect to network and get access to the desktop. 
• Hosted Virtual Desktops (HVD) - Moving virtualization into cloud creates hosted virtual desktop (HVD), where desktop images are centrally managed and maintained by a specialist hosting firm. (Amazon AWS, Azure, Firehost, DigitalOcean etc..)