In the past I have written about the importance of the stack – the combination of IT components such as the operating system, middleware, database, application, and management technologies. In virtualization, a similar focus is emerging around the “virtualization ecosystem” – systems that add value to the basic virtualization layer, and which shift the focus from the underlying infrastructure to a business environment.

Last week VMware sponsored my attendance at VMworld, where many vendors showcased support for this virtualization ecosystem. The clearest example was VMware’s new Virtual Appliance Marketplace, a selection of 300 pre-built, pre-configured and ready-to-run enterprise software applications, packaged with an operating system and delivered within a pre-built virtual machine. While important questions remain conspicuously unanswered about these virtual appliances and the marketplace – including significant doubts about security, maintenance, compatibility, and licensing – they build on the virtualization layer and add to the virtualization ecosystem to provide solutions, not just infrastructure.

Other vendors are adding to the ecosystem by incorporating virtualization into their products. For example at VMworld, Surgient promoted its Virtual QA/Test Lab Management System (VQMS), VMware announced VMware Lab Manager, and VMLogix unveiled VMLogix LabManager. Each of these products uses virtualization capabilities to help make application development faster, more effective and more efficient. I also spoke with executives from Kidaro, whose recently released Managed Workspace uses virtualization capabilities to deliver functional isolation and security enhancements for end-user desktops. While each of these new products has specific differentiators, they all contribute to the virtualization ecosystem by providing solutions, not just infrastructure.

The virtualization ecosystem was also a strong part of the recent Microsoft and Novell partnership announcement, which will see Microsoft spending $60 million over five years to market Linux and Windows virtualized scenarios. Speaking of Linux and open source, XenSource also announced last week its XenEnterprise for Windows product. Based on the open source Xen hypervisor, XenEnterprise is a multi-platform (Windows and Linux) virtualization product aimed squarely at the mass market and builds on and encourages the ecosystem surrounding the open source Xen virtualization engine.

Denise Dubie is senior editor with Network World.