Cloud offerings are largely verticalized silos of infrastructure, hosting services and even languages, said Sinclair Schuller, CEO and cofounder of software-as-a-service provider Apprenda. But the future, he said, will see the evolution of the application server architecture and its move to the cloud, creating a horizontal layer that broadens access and scales in a cost-efficient manner.

“Organizations won’t throw out their Java and .NET applications, so they realize they have to do something more” to get these applications leveraging the advantages of cloud deployment, Schuller said. Using the example of the recently announced VMforce cloud effort between Salesforce and VMware, he said, “Things are still very tightly coupled with clear dependencies on the Force back end.”

Middleware in the cloud, Schuller explained, handles such issues as data access and retrieval at that layer. By coupling middleware and multi-tenancy, components can be virtualized “so data from multiple customers can reside in a single database,” he said. “Applications execute in a single instance but flow orthogonally.” Multiple instances of an application don’t know they’re sharing a single instance of a database or data component, he said.

Apprenda is looking to democratize this high-end architecture with the June release of SaaSGrid Express, a free, downloadable version of the company’s SaaSGrid application server. The free tool has the main features and functionality of the app server product, and offers multi-tenancy and grid scalability, said Schuller. “You won’t see broad ISV adoption of the cloud without the infrastructure to scale,” he claimed. “Would you rather have the architecture share 1,000 customers across 1,000 servers, or 100 servers?”

By virtualizing the cloud stack, Apprenda is looking to achieve cost dynamics that make moving to the cloud a better option. “How software is written has implications on cost,” Schuller said. “You want as few cents on the dollar spent on the service.” Most people moving to SaaS have to scale for capacity, and cloud providers have to figure out how to offer the service cheaply, or movement to the cloud will be held back, he said.

SaaSGrid Express offers such services as application metering, monetization, subscription management and application life-cycle management, according to the product announcement. Further, it provides for billing and customer provisioning.

Apprenda cited Gartner research that predicted the market for SaaS applications will reach US$14 billion by the end of 2013, representing 14% of the total enterprise application market.