(Sorry, all you Web thieves; this isn’t an article about file-sharing.)

Oakland, Calif. — The personal-computer revolution for many Americans began in 1984, when their TV screens glowed with the surreal image of a woman in red track shoes, hurling a sledgehammer to shatter a huge video screen of a man preaching conformity.

That Super Bowl ad, Apple’s dig at the IBM PC, suggested a big idea: that personal computers could liberate users from the tyranny of centralized mainframe computers, which controlled and limited what they could do.

Nearly a quarter century later, a counterrevolution is in full swing. Known as “cloud computing,” it offers liberation of a different sort: the ability to access and share data anytime and anywhere via everything from a cellphone to a full-blown computer. But achieving that vision requires reliance on networks run by huge centralized clusters of computers reminiscent of the mainframes of the 1970s. This battle of visions is playing out in the corporate strategies of the world’s largest high-tech companies, with billions of dollars of revenue at stake. Buy software? How passe. | csmonitor.com

Tags: cloud computing, network, mainframe