You can see where Green Hat is headed. In the end, it's likely to be part of a platform-as-a-service offering, where many development services converge to aid in the application-building process. Green Hat virtualizes the testing phase of such a platform.

Other vendors have virtualized additional steps, such as capturing a code sequence in an application that contains a defect and sending it back to the developer who produced it or an expert who knows how to resolve it. As it goes from point to point, it's contained in a virtual machine that includes the appropriate operating system, enabling it to run instantly at each stop.

Theresa Lanowitz and Lisa Dronzek, of the market research firm Voke, name ITKO's LISA Pathfinder, acquired last year by CA Technologies, Parasoft's Virtualize, and Replay Solutions' ReplayDirector as pioneers in the field of defect virtualization. In addition, Microsoft Visual Studio's Test Professional 2010 includes the capability.

At GigaOm's Structure 2011 conference and other events, additional players have claimed to offer additional virtualization for the development process. Skytap supports the creation of development and test processes in virtual data centers, or a share of the virtualized servers in the enterprise data center. At each stage of the development process, the application moves from virtual server to virtual server and is available to be demonstrated to stakeholders, even as development continues on the code. Using virtual machines at each step of development both isolates unproven software until it's ready for deployment and gives different participants a crack at the new code from their own point of view.

Electric Cloud is also supplying a virtualized development environment for the private cloud, one that automates builds, tests, and deployments.

Predecessors to Green Hat include Akimbi and Surgient, suppliers of virtualized test centers or test lab managers, as they tend to be called. Akimbi was acquired by VMware in 2006 to become its Lab Manager product; Surgient was acquired by Quest Software in July 2010 to become part of its Cloud Automation platform.

Lanowitz and Dronzek say a fully virtualized development process--Microsoft comes the closest to having one--addresses some age-old challenges. As both developer and tester look at the same defect running in identical virtual machines, the developer no longer has the out of saying, "it works on my machine," they note.

If functionality testers give new code a green light, regression testers can illustrate where it falls short of working with other pieces of software in its planned deployment setting. Experienced operations personnel might also have suggestions after viewing performance in the virtual machine, prior to, rather than after, deployment.

The Voke researchers make ambitious claims for what fully virtualizing the development process might do. It will "take the most tedious, manual, and error-prone tasks and fully virtualize them for the benefit of faster time to market, increased quality, greater customer satisfaction, and lower costs." It will also collapse the silos that tend to separate development from test and both from operations, they claim.

I doubt if virtualization can make such perpetual challenges disappear at a stroke. Green Hat doesn't do all of the above, nor do any of the other pioneers in this space. Nevertheless, Lanowitz and Dronzek are pointing in the right direction. And what might have happened piecemeal over many years in the heterogeneous data center may happen more swiftly on a cloud platform.

Indeed, a virtualized development process fits into the type of higher level service being sought by today's cloud customers. A recent InformationWeek Report concluded that more cloud users are looking for higher level services than basic infrastructure as a service. Software development and test is going to be one of the first and most popular of those sophisticated services.

The evolution of virtualization has exposed complexities in application distribution and management that we couldn't have imagined in the days of disposable disk images. Our Application Virtualization report will help you get started. (Free registration required.)