Microsoft has applied for a patent on a pay-as-you-go computing model that would charge people only for the hardware, software, and services used.

The patent application, filed with the U.S. Patent and Trademark Office in June 2007, was released Christmas Day. While such patent applications don't always lead to products, they do give some inkling as to what the applicant is considering.

The application is for a method of operating a computer that presents to the user a catalog of options with a price associated with each. The total cost would depend on the number and kind of options selected. The charge for operating the computer could be a fixed rate for a specific time period, a onetime charge, or an hourly rate, the application says

Rentable hardware components could include processors, memory, and graphics controllers. Rented software and services could include word processing, e-mail, Web browsing, database access, and more. A computer modified for such a business model would need a metering agent to track usage and a security module to prevent tampering.

The application goes on to say that the new model would offer a more flexible approach than buying a computer and software that may or may not meet a person's needs over the lifetime of the system. Under the pay-as-you-go model, "When the need is browsing, a low level of performance may be used and when network-based interactive gaming is the need of the moment, the highest available performance may be made available to the user," the application says.

In explaining various bundles of software and computing power, Microsoft said an Office bundle, for example, could cost $1 an hour, a gaming bundle $1.25 an hour, and a Web browsing bundle 80 cents an hour.

Pay-as-you-go computing is not new. Amazon.com, for example, rents space in its data center for developers looking to build and deploy applications on the Web. The online retailer also rents storage. Companies offering previews of their own so-called "cloud computing" services include Google and Microsoft.