Microsoft researchers are developing a new operating system that's designed from the ground up to support Internet-based computing and multicore architectures and which could one day replace the company's storied Windows franchise.

The operating system, which currently goes by the development name Midori, is being built to solve problems that are beyond the scope of Windows, a so-called fat OS that was first developed before the Internet came into widespread use and most PCs had only a single processor.

It's possible that Midori is being designed for use in cloud computing scenarios, in which business applications reside on centralized servers and are accessed through the Web. Microsoft researchers also are building the OS with an eye to achieving better performance on multicore PCs, company documents show. To date, developers have had little success creating software that's able to fully harness the power of computers that feature two or more cores on a single chip.

Microsoft has said little about Midori and isn't commenting publicly on the project. But company research documents confirm that the project exists and is related to a public project called Singularity -- under which Microsoft developers are creating a slimmed down OS for use in the research community.

During a recent talk on a software tool called Chess, which is designed to check the status of programs that run in multithreaded architectures, Microsoft researchers Madan Musuvathi and Shaz Qadeer made reference to Midori by name in a PowerPoint presentation, documents show. In one slide, the researchers describe Midori as "OS in managed code."

Managed code refers to programs that can run in virtual environments across multiple computers, a setup that facilitates cloud computing, rather than working off a single CPU. It's a sign that Midori could possibly run as a virtual OS supported by Microsoft's Hyper-V virtualization platform.

In a separate, solo presentation at Princeton University in December, Qadeer noted that Chess supports Win32, Microsoft's Common Runtime Language, and "Midori OS," according to a copy of Qadeer's presentation viewed Wednesday by InformationWeek.

Midori, if it makes its way to the market, could solve a number of problems for Microsoft. The current version of Windows, known as Vista, has been poorly received by IT managers. Many view it as too large and resource hungry, and too desktop-centric, for an era in which much of business computing's heavy lifting is migrating to the Web.

And the forthcoming Windows 7, set for release in 2010, may do little to help the situation. Microsoft has confirmed that Windows 7 is being built from the same code base as Vista and architecturally will not significantly differ from its predecessor.