Utility computing was supposed to be about pay-as-you-go computing resources. But contracts, commitments, and minimum fees diluted the concept. Sun Microsystems will try to change that this week when it introduces a utility computing service that doesn't require a contract or a long-term commitment.

Sun has been offering commercial utility computing services for several years. The new service--"public" utility computing--can be purchased via a Sun portal for $1 per CPU hour. It should appeal to companies offering software as a service and other businesses that don't want to invest heavily in a computing infrastructure, Sun officials say.

But there are catches: Customers must use the Solaris 10 operating systems on Opteron-based x86 servers. "The pay-for-use model is an innovation, but there is a very unflinching standardization," Forrester Research analyst Frank Gillett says.

IBM and Hewlett-Packard also offer utility computing. Sun's new offering doesn't deal with crucial issues such as liability, confidentiality, and security, David Gelardi, VP of deep computing at IBM, says in an E-mail. "Sun continues to trivialize these issues, perpetuating a failed strategy of driving the software stack and not serving clients' real needs," he writes.

Virtual Compute, a customer and competitor of Sun, offers a utility computing service at 25 cents per CPU hour for customers who commit to a six-month contract. For customers who don't want to make that commitment, Sun's offering makes sense, CEO Edward Hawes says. He bought access to 1,400 CPUs from Sun last fall to fulfill short-term commitments to oil and gas customers during a period in which Virtual Compute's own capacity was completely utilized. Says Hawes, "I think there are applications that would run in the Sun portal environment very well."