Microsoft has made its Virtual Hard Disk image format specification available to users at no cost and with the guarantee that the Microsoft will never take legal action against them under its Open Specification Promise.
Microsoft issued the Open Specification Promise on its Interoperability Web page Sept. 12, when the company promised not to take any legal action against developers or customers who use any of 35 Web service specifications.
The company's VHD format has been available since May 2005 and captures the entire virtual machine operating system and the application stack in a single file.