What's the beef here then? Well in a nutshell Diskless PCs and Vista Enterprise Centralised Desktop open up new methods for IT departments to roll out and manage their desktop estate. These new methods introduce different benefits so allow me to describe the different technologies.
The Diskless PC: Simply put this is a PC without a disk! No brainer huh? It's a PC that only has processor, memory, networking, graphics card etc whilst the machine's hard disk is located centrally in what could be a SAN or other datacenter setup. This scenario is enabled by high speed networks and reliable network infrastructure that has high QoS (quality of service) so effectively the hard disk IO travels over the wire and is processed locally by the other computer components.
Historically this kind of PC wasn't catered for under Microsoft licensing but last year with Vista we announced a new licensing scheme for enterprise customers that catered for the increased customer demand for this technology.
It's not currently a common setup but for organisations that consider security of data an absolute top priority this is a very interesting option.
Vista Enterprise Centralised Desktop (VECD): So a slight twist on this one. VECD allows a desktop PC running Windows or a thin client machine (typically running Windows CE or Windows Embedded) to access a Virtual Machine that is stored and managed centrally on a server running Virtual Server 2005 R2 (or Hyper-V in future). In this scenario you are harnessing the server's horsepower to run the operating system and the desktop comes back to the local machine.
This capability is delivered via a subscription based licensing agreement which is an option when you buy Windows Vista Enterprise (available through Software Assurance).
Microsoft, Windows Vista, Diskless, PC, Centralised, Desktop, Software+Services, SaaS