Development of Windows 8

Windows 8 development started before Windows 7 had shipped in 2009.[17]  At the Consumer Electronics Show in January 2011, it was announced that the next version of Windows would add support for ARM system-on-chips alongside the existing x86 processors produced by vendors, especially AMD and Intel. Windows division president Steven Sinofsky demonstrated an early build of the port on prototype devices, while Microsoft CEO Steve Ballmer announced the company's goal for Windows to be "everywhere on every kind of device without compromise."[18] [19] [20] [21]  Details also began to surface about a new application framework for Windows 8 codenamed "Jupiter", which would be used to make "immersive" applications using XAML (similarly to Windows Phone and Silverlight) that could be distributed via a new packaging system and a rumored application store.[22]

Three milestone releases of Windows 8 leaked to the general public. Milestone 1, Build 7850, was leaked on April 12, 2011.[23]  It was the first build where the text of a window was written centered instead of aligned to the left. It was also probably the first appearance of the Metro-style font, and its wallpaper had the text ''shhh. let's not leak our hard work''. However, its detailed build number reveals that the build was created on September 22, 2010.[24]  The leaked copy was Enterprise edition. The OS still reads as "Windows 7". Milestone 2, Build 7955, was leaked on April 25, 2011. The traditional Blue Screen of Death (BSoD) was replaced by a new black screen, although this was later scrapped.[25]  This build introduced a new ribbon in Windows Explorer. Build 7959, with minor changes but the first 64-bit version was leaked on May 1, 2011. The "Windows 7" logo was temporarily replaced with text displaying "Microsoft Confidential". On June 17, 2011, build 7989 64-bit edition was leaked. It introduced a new boot screen featuring the same fish as the default Windows 7 Beta wallpaper, which was later scrapped, and the circling dots as featured in the final (although the final version comes with smaller circling dots throbber). It also had the text Welcome below them, although this was also scrapped.[26]  It is worth mentioning that most of these leaks "hid" the main Metro UI features that were to come in tweak known as Red Lock in order to prevent relevant leaks. A patch named Red pill was necessary to reveal the new Metro UI as well as the redesigned Start Screen, Lock Screen and apps.[citation needed]

On June 1, 2011, Microsoft unveiled Windows 8's new user interface, as well as additional features at both Computex Taipei and the D9: All Things Digital conference in California.[27] [28]

The "Building Windows 8" blog launched on August 15, 2011, featuring details surrounding Windows 8's features and its development process.[29]