Microsoft today shipped Windows 8.1, the free upgrade to Windows 8, with CEO Steve Ballmer calling it "a refined blend" of what many critics had called a jarring disconnect between its two radically different user interfaces.
The upgrade, which had been announced weeks ago, hit the Windows Store today during the first minutes of the opening keynote of BUILD, Microsoft's developers conference that runs through Friday in San Francisco.
"Windows 8.1 is a refined blend of our desktop experience and our Modern user experience," said Ballmer, relying on a coffee metaphor.
Both Ballmer and Julie Larson-Green, who heads Windows development, boasted of the quick turn-around from Windows 8, which launched last October, to Windows 8.1, which will ship in final form this fall.
"This is absolutely a rapid release cycle," said Ballmer, following quickly with a truncated version of his famous chanting. "Rapid release, rapid release. And this is not a one-time thing. It's the new norm for everything we do."
Larson-Green also touted the faster cadence, saying it showed "how much more responsive we've become" and pledging "continuous improvement" to Windows.
Although some analysts were skeptical that Microsoft could pull off such a major departure from its historical development process, the fact that it debuted a public preview eight months after the retail launch of Windows 8 was clearly a win in the eyes of Frank Gillett, an analyst with Forrester Research.
"Just having the event [now] lets them say, 'Look, it's eight months later, and we have the next version of Windows ready,'" said Gillett in an interview Tuesday.
Larson-Green closed her portion of the keynote by echoing her boss, Ballmer, making "refined" the company's slogan of the day. "Windows 8.1 is Windows 8 refined," she said.
Windows 8.1 can be downloaded from the Windows Store, Microsoft's market for its Windows 8 and Windows RT "Modern," née "Metro," apps, by first browsing to this page on the Microsoft website, then from there downloading a small 9MB installer file. Running that file restarts the PC or device and redirects to the Windows Store, where the actual upgrade can be retrieved.
Microsoft has promised that it will also offer Windows 8.1 as an .iso-formatted file that can be burned to a DVD or copied to other removable media, like a flash drive, for later installation or for upgrading multiple PCs and devices.
That .iso file, however, was not available Wednesday. "Windows 8.1 Preview ISO files will be made available on this site within the next day," the company said on the download site.
Systems running Windows 8 Enterprise, an edition available only to volume license customers, must upgrade using the .iso option. And bootable media containing the .iso file must be used to upgrade PCs running older versions of Windows, including XP, Vista and Windows 7. Those users must enter a generic product activation key -- NTTX3-RV7VB-T7X7F-WQYYY-9Y92F -- during the upgrade installation, said Microsoft.
This article, Microsoft restarts Windows push with 'refined blend' Windows 8.1 beta, was originally published at Computerworld.com.
Gregg Keizer covers Microsoft, security issues, Apple, Web browsers and general technology breaking news for Computerworld. Follow Gregg on Twitter at @gkeizer, on Google+ or subscribe to Gregg's RSS feed . His email address is email@example.com.