IT managers disagree on a definition of cloud computing, but they agree that it's either already in their budgets or soon will be. And they expect to share responsibility for cloud computing with application developers and business stakeholders.

Those were two of the conclusions that came out of a June survey by Applied Research - West, on enterprise adoption of cloud computing. The survey was sponsored by F5 Networks, a network access and interoperability vendor.

The survey found that 66% of 250 IT managers interviewed by telephone said they have dedicated budget funds for the cloud. In addition, 71% said they expect cloud computing budgets to grow over the next two years.

One conclusion from the survey is that cloud computing is gaining critical mass: 82% of the respondents said they are "in some stage of trial, implementation or use of public clouds," and 83% said the same for use of private clouds.

Participating firms had at least 2,500 employees, with a median of 75,000. Those interviewed included IT managers, 37%; IT directors, 23%; VPs, 24%; and senior VPs, 16%. No CIOs were included in the survey, Applied Research - West said.

IT managers agree that one form of cloud computing is SAAS or software as a service, but they do not see it as the most important element, said Lori MacVittie, technical marketing manager for F5, in an interview.

Three-quarters said they see platform as a service, such as when Salesforce.com offers database services and tools for customizing its applications or building new ones, as a form of cloud computing.

In addition, 60% said they see infrastructure-as-a-service or Amazon's EC2 as cloud computing. Infrastructure-as-a-service is where a service provider supplies hardware and some software, such as Amazon's SimpleDB database service, and runs a configuration of an IT organization's software as an external resource.

As IT managers adopt cloud computing, they are looking to fill in the missing pieces behind the simplified services now available. Among other things, 90% said they want control over who can access their cloud resources. "Who has access? How is it controlled? Who can self-provision a server," said MacVittie.

Another 89% named network security as a core cloud technology, as well as 88% citing server and storage virtualization as "essential technologies in the cloud," she said.

The main driver toward cloud computing is the efficiency that stems from using public clouds instead of further building out the IT infrastructure internally, according to 77% of respondents. Public cloud computing reduces capital costs, according to 68% of those surveyed, and eases staffing issues, said 61%. When it comes to private clouds, the drivers include reducing capital cost, 63%; agility and easing staffing issues, both 50%.