VMware's virtual machine disk format specification for defining and formatting virtual machine environments is now openly available, downloadable and free of charge. This will enable use by all developers, software vendors and projects and includes open licensing compatible with those operating under open source licenses such as the GPL. In addition, VMware is committed to supporting any other open virtual machine disk formats broadly adopted by customers and working toward converging on open standards in this area.

"Encouraging the use of a common virtual machine disk format should lead to better interoperability across the industry. VMware's initiative to open up its virtual machine disk format -- a format that already is widely used in the industry -- is an important development in the virtualization space and will benefit customers and ISVs alike," said Al Gillen, research director of system software at IDC. "We see the broad use of a common virtual machine disk format leading to more products to choose from, along with interoperability across customers' environments."

A virtual machine encapsulates an entire server or desktop environment in a file. The virtual machine disk format specification describes and documents the virtual machine environment and how it is stored. Patch, provisioning, security, management, backup and other infrastructure solutions for virtual machine environments all heavily depend on the virtual machine disk format. Based on this dependency, having an open and unrestricted virtual machine disk format is critical to the broad-based development of new solutions and value-add for virtual environments.

"VMware is offering our virtual machine disk format openly and freely to the virtualization industry," said Brian Byun, vice president of products and alliances at VMware. "We are doing so because we believe open and freely- useable specifications should increase the availability of complementary products, provide customers unfettered choice and increased interoperability in their virtualized IT environments and further expand the virtualization market which is good for VMware."

Software vendors like Akimbi Systems, Altiris, BMC Software, IBM, PlateSpin, rPath, Surgient, Symantec and Trend Micro are leveraging the VMware virtual machine disk format specification to develop value-added products for customer virtual infrastructure environments.