I think a lot of people confuse these two virtualization technologies and maybe you're one of them. The distinction is not apparent from the names given to them but rather in the scale of the technologies behind them. Desktop virtualization means that you run a virtual machine on your desktop computer. Virtual desktop infrastructure (VDI) is a data center technology that supplies hosted desktop images to remote users. There is, as you can see, a huge difference between the two.
But, before I discuss more about desktop virtualization or VDI, I need to establish a baseline of information and terminology so that we're speaking the same language.
The basic premise behind virtualization is that it is a "computer within a computer." An operating system runs within an application (virtualization software) that emulates or abstracts actual hardware into a standard set of virtual hardware. Virtual hardware consists of virtual disks, virtual CPU(s), virtual memory, virtual display, virtual serial ports and so on.
Some examples of this type of virtualization are Oracle's VirtualBox, Parallels Desktop, VMware Workstation, QEMU and Microsoft's Virtual PC.
Desktop virtualization is the simplest form of this computer within a computer concept. Generally speaking, desktop virtualization is a single desktop computer that hosts a single guest virtual machine. The virtual machine can be a Linux system, a Windows desktop or server, a FreeBSD system, a DOS virtual machine, a Novell server, a Mac OS X or another operating system.
This type of virtualization makes running another operating system easier and more efficient than dual booting for the operator. The desktop system user/operator can run a host system simultaneously with the guest and enjoy the advantages of both systems. Application developers can test new software on virtual machines without the need for dozens of physical systems sitting around losing value.
And, virtual machines are much easier to rebuild should something go wrong. Reimaging a physical system might take several hours whereas creating a new virtual machine takes minutes.
VDI is an alternative to traditional desktop computing. The theory behind it is that removing the desktop operating system from a local computer and placing it in a shared hosting environment, like a cloud hosting data center, relieves some of the costs associated with desktop support. There seems to be a great deal of myths, paranoia and general resistance against VDI. Some of that resistance stems from the assumed control one has over a local operating system and cloud security.
At the hardware level, VDI consists of virtual host system clusters that provide the computing horsepower for groups of virtualized desktop systems. In other words, you have a group of VMware ESX host machines on which your Windows 7, Windows Vista, Windows XP and Linux desktop systems run. You connect to your desktop via remote connectivity software from any Internet-connected device.
You can connect via a secure virtual private network (VPN) connection so that your information travels to and from the remote desktop in an encrypted format. Contrary to popular belief, these hosted systems are no more or less secure than any other desktop system from a pure software perspective. You still must have anti-spyware, anti-malware, anti-popup and firewall protection installed on every one. Requiring a secure connection between the remote client and the desktop operating system makes the service safe to use.
If you have any questions about desktop virtualization or VDI, please ask in the Talkbacks so that everyone can benefit from the dialog. You may contact me directly via the Contact link in the left pane.