Long Zheng has uncovered an interesting job posting at Microsoft, seeking engineers to "bring virtualization into the mainstream." It’s one of the few (no doubt inadvertent) leaks in the Windows 7 feature set we’ve yet seen:
In Windows 7, our team will be responsible for creating, mounting, performing I/O on, and dismounting VHDs (virtual hard disks) natively.
Virtualization technology has been a great success with Virtual Server and Hyper-V. With native OS support on the horizon it will become an even greater hit. Our team is making this a reality in Windows 7. Consider the simplicity of backup using a VHD, or the portability of a virtual disk backed by a single file. These are a few reasons why this technology is poised to be one of the greatest features in Windows 7–come help us achieve this goal.
In an update, Long notes that a few people he’s talked to have "expressed their concern this may not make it to RTM."
Maybe, but it’s worth noting that support for the VHD format is in Windows Vista today, in the form of the Complete PC Backup program found in the Business, Ultimate, and Enterprise editions. (Here’s an August 2006 demo of the feature, which also mentions the capability of mounting saved VHD files.) So the operating system already has code to create and perform I/O on VHD files.
During the beta for Vista, I recall product managers talking about how they wanted to include a tool to mount and unmount those backup images but ran out of time. That was in summer 2006, around the time RC1 was declared, and presumably the teams responsible for that code continued working on it. No doubt much of the work that has gone into Hyper-V (RC1 just shipped) and Virtual PC 2007 (Service Pack 1 just shipped) could also make it into Windows 7.
Given that base, it’s a safe bet that development of this feature is pretty far along. Far enough, in fact, that whoever wrote that job posting has enough confidence to predict that "this technology is poised to be one of the greatest features in Windows 7." It might have a better chance of making it into the final release than those skeptics think .
Update: In the comments, Greg Duncan points out that Vista users can install the VHDMount utility from Virtual Server 2005 R2 SP1 and use it to mount/unmount VHD files, although it’s not easy. More details in his post here.
From the sidebar at Greg’s blog, I see that he has been living up to his blog’s name by working on some cool-looking Windows LIve Writer templates as well. Nice!