Taking the stage today at Oracle OpenWorld in San Francisco, salesforce.com boss Marc Benioff hit back at criticisms from Oracle CEO Larry Ellison about his firm’s cloud credentials.

During his keynote that opened OpenWorld on Sunday evening, Ellison said that salesforce.com was not real cloud computing and had a weak security model. Siding with Amazon’s definition of cloud computing – a platform for building and deploying applications – Ellison said: "[Cloud is] a platform for standards-based applications. Salesforce has a weak security model – everyone’s data co-mingles on the same platform and if that goes down, everyone goes down. It is not fault tolerant, it’s not virtual and it’s not elastic."

Benioff attempted to downplay Ellison’s comments as soon as he walked on stage: "We come in peace," he declared. "I want to thank Larry for that great advertising on Sunday night. We are cloud people, a peaceful people."

He then addressed some of Ellison’s accusations directly, particularly concerning the definition of cloud computing. "Our definition of cloud computing is multi-tenant, it’s faster, half the cost, pay as you go, it grows as you grow or shrinks as you shrink. It is extremely efficient."

He then turned his attention to Oracle’s new Exalogic Elastic Cloud and declared: "We’re not going to show you computers taller than you. We’re not going to show you a cloud in a box because clouds don’t come in a box. They never have. That’s the whole idea."

During Ellison’s talk on Sunday Benioff actually Tweeted "Beware of the False Cloud" and then referenced a reply from Amazon’s CTO Werner Vogels that said: "litmus test: if you have buy more hardware just to get started it is not a cloud…".

So while Larry Ellison may side with Amazon on the definition of cloud computing it seems that Amazon doesn’t feel the same way.