In an overhaul of its platform group, Microsoft is redistributing responsibilities of top managers in charge of its operating systems. The move is intended to improve software quality, bring agility to Windows development, and better align development groups with the company's revenue-reporting structure.

A new Windows Core Operating System Division will be managed by senior VP Brian Valentine, who had been responsible for all Windows development for the past five years. Among the technologies within the new division are "core" performance, security, and networking; device management; setup and deployment tools; automated code testing; and productivity tools for Microsoft developers.

The creation of a core development unit could help Microsoft develop platforms tailored for different customer segments, says group VP Jim Allchin. The Windows client business will now report directly to Allchin; overall responsibility for Windows servers shifts to the server and tools business headed by senior VP Eric Rudder.

The changes are unrelated to, and won't affect the timing of, the next-generation Longhorn operating system, Allchin says. Nor, he says, is the move influenced by the growing popularity of open-source software.