There are many differences between VDI vs. Terminal Services, but they can all be summed up as differences between operating systems and how sessions are handled.
Windows Terminal Services -- now called Remote Desktop Services (RDS) in Windows Server 2008 and up -- was Microsoft's early attempt at creating an environment where users were not dependent on the local desktop. Users connect to a session by way of a Remote Desktop Protocol (RDP)-based client, the same way they do in virtual desktop infrastructure (VDI). The similarities between the two environments end there, however.
In a Terminal Services environment, the user sessions are based on Windows Server instances. As such, the sessions become the isolation boundary between one user and another. Users actually work within a Windows Server operating system rather than a desktop operating system, such as Windows 7. In some cases, this can be problematic, because not all applications will run properly (or at all) on a Windows Server OS.
VDI works differently. You can base VDI images on Windows Server if you want to, but that's not the only component at work. Instead, users connect to a connection broker that links the user session to a virtual machine running on top of a hypervisor. This virtual machine typically runs a Windows desktop operating system, such as Windows 7 or 8.
VDI environments tend to be more complex than Terminal Services environments. Despite the added complexity, many administrators prefer VDI to Terminal Services because VDI allows the user to work in a familiar desktop OS, and because VDI tends to be a less susceptible to application compatibility issues.
About the author:
Brien Posey is a Microsoft MVP with two decades of IT experience. Previously, Brien was Chief Operating Officer for a national chain of hospitals and healthcare facilities.
