Microsoft’s Tami Reller, corporate vice president of Windows, kicked off Microsoft’s Worldwide Partner Conference with an announcement that was widely expected: Windows 8 will be available in late October.

Ms. Reller said that the OS would be released to manufacturing partners in early August.

“Windows 8 is simply the biggest deal from our company in at least 17 years,” Microsoft CEO Steve Ballmer said during his conference keynote. “It’s a huge opportunity for our partners, and a very big deal for Microsoft.”

“With Windows — Windows 8, Windows Phone 8, Windows Server 2012 and Windows Azure — and Office 365, there’s never been a better time to be a Microsoft partner,” Mr. Ballmer said.

“This is an epic year.”