Defections are rare from the ranks of IBM Fellows, who hold the company's highest technical position. Ferguson, one of 65 IBM Fellows among a technical workforce of more than 200,000 employees, spent two decades with IBM Research.
Although Ferguson always resisted being credited as WebSphere's patriarch, he led the team that created the software that became IBM's WebSphere line, the linchpin of its integration and middleware portfolio. Later, he chaired IBM's Software Group Architecture Board, which coordinates integration of all IBM software lines.
Ferguson will be one of Microsoft's 15 technical fellows, holding the title of technical fellow in platforms and strategy in the software giant's Office of the CTO. Ferguson and Microsoft weren't available for comment, but a biography posted on Microsoft's Web site said Ferguson will focus on "understanding the trends, architecting and piloting the implications for existing and new products, and evangelizing Microsoft's vision."
Ferguson's departure comes on the eve of Lotusphere, IBM's conference devoted to the Lotus software it acquired years ago and now is trying to integrate more deeply with its other software lines. Meanwhile, Lotus Notes creator Ray Ozzie is gathering talent at Microsoft to help refashion the company to tackle new challenges, such as the software-as-a-service movement and the rise of Google.