Microsoft will start selling Windows 8 on Oct. 26, the same date its computer-making partners launch new hardware equipped with the operating system. Microsoft will also -- which runs the Windows RT spin-off OS -- that day.

Now 59, Allen is worth an estimated $15 billion, enough to rank No. 20 on the 2012 . Company co-founder Bill Gates leads that list with a $66 billion net worth, while current CEO Steve Ballmer places No. 19 with $15.9 billion.

Gregg Keizer covers Microsoft, security issues, Apple, Web browsers and general technology breaking news for Computerworld. Follow Gregg on Twitter at , or subscribe to . His e-mail address is .

in Computerworld's Operating Systems Topic Center.