What is the difference between cloud computing and sharing remote hardware and software? "Patrick Harr, Hewlett-Packard's vice president of global cloud strategy, argue that recent technological and business developments make 'the cloud' a truly different way of using computer resources. ... Harr says two key advances distinguish cloud computing from earlier versions of remote hardware and software rental and mark 'a fundamental technological shift'. One is 'multi-tenancy,' in which many businesses can take simultaneous advantage of a huge pool of powerful resources such as HP's tens of thousands of servers."