During the D9 conference in California, Microsoft’s Steven Sinofsky began showing off Redmond’s upcoming Windows 8 operating system, fully optimized for tablets. According to AllThingsD, which got an early peak at the OS, Microsoft’s ultimate goal was to create an OS that could run on a home computer just as well as it could run on a portable 8-inch tablet. The new start screen, pictured above, shows a tile-based interface that’s strikingly similar to Microsoft’s Windows Phone operating system and makes use of the company’s Metro UI. Windows 8 includes Internet Explorer 10, and can run applications that are designed for desktop use, as well as HTML 5 and Java applications that will run better on tablet-sized devices that may provide less power. Sinofsky told AllThingsD that Windows 8 will deliver a new business model for developers, an app distribution mechanism — assumed to be a storefront — and a touch interface. Microsoft reportedly started working on the operating system when it shipped Windows Phone 7. “We really did take a step back after Windows 7,” Sinofsky told AllThingsD. “We were clearly influenced ourselves by phones.” The current demo products run on devices with Intel processors, although Microsoft reportedly also has devices powered by ARM processors, too. There’s still no word on when we’ll see the first Windows 8 devices hit the market, but we’re definitely excited with what we’re seeing so far.