Confirmed on Building Windows 8 blog, Windows 8 enables easy access to the contents of two important file storage formats, ISO and VHD. The former is a long lost soul in Windows, despite the fact that most of the image files from Microsoft have been packed in that format. For the latter, it comes naturally because indeed VHD is a Microsoft thing.
Working with ISO files in Windows 8
I have used a number of 3rd party virtual drives to get access to the ISO format of data, Virtual Clonedrive is the one I am currently using. But once Windows 8, there is no more needs to have those 3rd party tools for that matter. Bad news to those ISVs though.
As revealed, accessing ISO files in Windows 8 is just a matter of double-clicking the file or clicking Mount on the Action tab.
Once mounted, a new drive letter appears for the virtual CDROM/DVD drive that Windows seamlessly creates. The contents of the ISO are accessible just as they would have been had you inserted the CD/DVD media into a physical optical drive.
Once you are done with the ISO file, you can virtually “eject” it and the virtual drive created earlier disappears.
However, there is still one piece missing. You still can’t create the ISO images either from existing optical media or data. It would be nice if it could. You still need tools like ImgBurn to do the such job.
Working with VHD files
The Virtual Hard Disk (VHD) format is a publicly-available image format specification that allows encapsulation of the hard disk into an individual file for use by the operating system as a virtual disk in all the same ways physical hard disks are used. In Windows 7, you would need to mount the VHD files through disk manage before being able to access their data.
In Windows 8, accessing a VHD is as simple as what it’s done with ISO files with one important difference. Instead of showing as a CDROM/DVD drive, it would appear as a removable drive, like a new hard drive.
Underneath the covers, Windows provides a virtual drive letter pointing to the volume within the VHD. You’ll notice that the icon for the drive G: below is the same as the icon for a VHD file. You can then work with the VHD just like any other file storage in your system, whether you are modifying, adding, removing, or just reading files.
Same as working with ISO files, you can “eject” the media once you’ve done with the file. All changes you’ve made remain saved within the image.