Microsoft delivered on its promise and XDrive is now a virtual reality called Windows Azure Drive. This allows you to backup Windows applications automatically to the Micrsoft Azure. Read details here.
Windows Azure drive is implemented as a NTFS formatted Virtual Hard Drive for persisting data which may be accessed. It is implemented as Windows Azure Page Blob which means if the application using the drive crashes for any reason the data is still available.
In order to use this drive you should use Windows Azure Guest OS 1.1 (starting Feb 01,2010). Prior
December version was 1.0.
The APIs which goes with this support the following operations:
Get Mounted Drives
More details are found here.
Technical documentation (Brad Calder and andrew Edwards ) may be found here.
In a very short time the verison has gone up from 1.0 to 1.1 where a number short comings of 1.0 has been fixed. The support for the forthcoming VS2010 RC is also included. The developers need to be on thier toes if this pace is kept up in releasing versions at this clip. How does the backward compatibility work? What happens to applications created with VS2010 Beta 2 with the new 1.1 version of Windows Azure?
These will surely crop up in the forums in the near future.