An anonymous reader writes with this Venturebeat story about how Windows 10 is different from previous versions because of the way it was designed, including 15 public preview builds, and how much work is still being done. Windows 10 for PCs arrived two weeks ago. Thankfully, we don't need to wait years to say this will be a Microsoft operating system release like no other. The most obvious clue is not the fact that Windows 10 was installed on more than 14 million devices in 24 hours, that you can get it for cheap or upgrade to it for free, nor even that it ships with a digital assistant and a proper browser. No, the big deal here is that Microsoft is turning its OS into a service, and that means as you read these words, it's still being built. For the next few years, we'll be getting not just Windows 10 updates and patches, but new improvments and features. This is possible because Microsoft built this version very differently from all its previous releases.