Windows 8 developer preview gets 500,000 downloads in 12 hours

Microsoft chief executive Steve Ballmer has revealed that the Windows 8 developer preview has been downloaded 500,000 times, just 12 hours after release.

Ballmer told investors at the firm's Build conference in Anaheim that reaction to the early build of Windows 8 has been positive, and that the platform will be at the core of Microsoft's future strategy.

"Certainly the release of the developer preview of Windows 8 is just that: a developer preview. We still have a lot of work to do on Windows 8," he told delegates.

"Windows is at the centre of our strategy and we feel very comfortable. That's a smart thing to do for our customers and our shareholders."

Ballmer is confident that Microsoft has found the right formula to bring the "the best of tablets and PCs together".

"We have to re-imagine Windows and we have to change Windows, but there is absolutely no reason not to build on the incredible technology strengths and base of applications, skills and brand strengths in Windows," he said.

Ballmer was also candid in his assessment of the Windows Phone platform, which was released just under a year ago. He acknowledged that Windows Phone has been not been as successful as anticipated, but remained optimistic about the future.

"We haven't sold quite as many [Windows Phone handsets] as I would have hoped in the first year, [but] I'm very optimistic on where I think we can be," he said.

"With a little bit more effort and energy - the level of enthusiasm from the customer base is high enough - we've just got to kick this thing to the next level."

Ballmer also gave an update on the Office business which, together with the Server and Windows platforms, helps to generate $15bn in revenue.

"Office is our biggest business and is growing rapidly. The launch of Office 365 in June is a big deal competitively and in terms of giving us opportunities to reach new customers and grow revenue," he continued.

"Bing [is also] a very important investment as it relates to the opportunities for search, and it is a fundamental set of core technologies that we absolutely need to invest in broadly to be in the devices business and cloud platform business."