VHD meaning in Computing ?

VHD (Virtual Hard Disk) and its successor VHDx are file formats representing a virtual hard disk drive (HDD). They may contain what is found on a physical HDD, such as disk partitions and a file system, which in turn can contain files and folders. They are typically used as the hard disk of a virtual machine, are built into modern versions of Windows, and are the native file format for Microsoft's hypervisor (virtual machine system), Hyper-V.

The format was created by Connectix for their Virtual PC product, known as Microsoft Virtual PC since Microsoft acquired Connectix in 2003. VHDx was introduced in Windows 8/Windows Server 2012 to add features and flexibility missing in VHD that had become apparent over time.

Since June 2005, Microsoft has made the VHD and VHDx Image Format Specifications available to third parties under the Microsoft Open Specification Promise.