Trying to keep up with virtualization technology can be mind boggling. While I am a sales engineer, when in the office I am charged with setting up multiple test environments in which to run our products. I have setup XEN Server, XEN Desktop, VMWare VDI and then View, XEN App, App-V, and more. Soon I will be given one of our old production ESX boxes to add to the test environment. Since I started at triCerat I have watched Presentation Server become XEN App, VMWare VDI become VMWare View, and now SoftGrid become App-V. I have found that there seems to be about seven virtualization categories at least.
Client Hypervisor – Software that installs on a desktop OS, e.g. Windows XP, Windows Vista, Mac OS
Bare Metal Hypervisor – The hypervisor installs directly on the hardware without any underlying OS. Offer by some Vendors as an embedded option on servers.
Software Hypervisor – Requires an underlying OS, e.g. Windows Server 2008.
Centralized VDI – Virtual Desktops are running on a virtual server of some type. Clients connect via protocols such as RDP and ICA.
Client-based VDI – Virtual Desktops are running on the client’s machine using a client hypervisor. Images can be managed centrally.
Cloud Computing – A dynamically scalable virtual infrastructure (physical infrastructures are possible) that provides services over the Internet.
App Virtualization – Applications packages/profiles are created on a central store and then streamed/delivered to the client when needed.
Below is matrix showing where the big three come into play for these technologies.
VMWare
Citrix
Microsoft
Client Hypervisor
Workstation, Fusion
N/A
Virtual PC
Bare Metal Hypervisor
ESX/VI3, ESXi
XEN Server
Hyper-V
Server Software Hypervisor
VMWare Server
XEN Hypervisor1
Virtual Server
Centralized VDI
View
XEN Desktop
3rd-party2
Client-based VDI
ACE
N/A
MED-V (formerly Kidaro)
Cloud Computing
vSphere 4
Citrix Cloud Center (C3)
Azure
App Virtualization
Thin App (formerly Thinstall)
XenApp (formerly Presentation Server)
App-V (formerly SoftGrid)
1 = The open source XEN Hypervisor can be installed on Linux varients.
2 = Microsoft has partners with Citrix and Quest to provide the brokers in their VDI solution.