The Xbox 360 was officially unveiled on MTV on May 12, 2005, with detailed launch and game information divulged later that month at the Electronic Entertainment Expo.
Its Xbox Live service allows players to compete online as well as download games and additional content.
Due to its early launch, the Xbox 360 has a one-year lead on both of its competitors, Sony's PlayStation 3 and Nintendo's Wii.
Xbox Live Silver is free of charge and allows users to create a user profile, join on message boards, access Microsoft's Xbox Live Arcade and Marketplace and talk to other members.
Xbox Live Gold has the same features as Silver, plus online game playing capabilities.
Microsoft XNA also includes other components such as the XNA Framework and XNA Build. Anyone can develop a game using XNA Game Studio Express, an IDE for homebrew developers, which was initially released in beta form on August 30, 2006.
Microsoft has stated that they intend to release more emulation profiles as they become available, with a goal of making the entire Xbox library playable on the Xbox 360.
Xenos contains 48 unified shader units, which are capable of both vertex and pixel shading operations. This is in contrast to older graphics processor designs which utilize separate specialized units for these tasks.
