Alex Barrett with TechTarget Magazine reports from WinHEC:

Microsoft's first program to spur creation of Virtual Hard Disk-based appliances is going well, but partners want more out of this good thing. Those attending WinHEC today asked for a number of improvements, including fewer Windows distribution restrictions, VHD (virtual hard disk) format updates and more.

It's been several months since Microsoft announced the formation of its VHD Test Drive program, which gives independent software partners (ISVs) the ability to redistribute Windows operating systems (OSes) within a virtual appliance based on its VHD format. Overall, the company is pleased with its progress.

Speaking on a WinHEC panel devoted to VHDs, Mike Neil, Microsoft general manager for virtualization, said, "We've been very happy with the reception around VHD and the VHD specification. We've seen uptake among all communities – including the open source community – and it's going to be great to see what products come from that."

In addition to Microsoft virtualization software, VHD -- Microsoft's analog to VMware's proprietary VMDK format -- is used as the default virtual machine (VM) format by XenSource and Virtual Iron, while VMware and Parallels virtualization software can also run VHD-based VMs by converting them in to their own formats.

Read the entire article, here.