Xbox
Released in 2001, the Xbox control pad was the first controller made for the original Xbox. The Xbox controller features two analog sticks, a pressure-sensitive directional pad, two analog triggers, a Back button, a Start button, two accessory slots and six 8-bit analog action buttons (A/Green, B/Red, X/Blue, Y/Yellow, and Black and White buttons). The standard Xbox controller (originally nicknamed the "Fatty" and later the "Duke") was originally the controller bundled with Xbox systems for all territories except Japan.
Xbox One
At its launch, the Xbox One did not have native backward compatibility with original Xbox or Xbox 360 games. It had been a desired launch feature by Microsoft and had been actively under development as early as 2007 under the "Trioxide" program as to get Xbox 360 code to run on 64-bit hardware. Rather than going the route of the initial PlayStation 3 which included a core PlayStation 2 system-on-a-chip processor, the Xbox One hardware was designed to include support for Xbox 360 XMA and texture processing on hardware, knowing this would be difficult to replicate in software. Following criticism of its plan for an "always on" console from the May 2013 announcement, Microsoft had to put significant effort to prepare the Xbox One software for a revised approach, and the backwards compatibility development work were put on hold. Interim solutions were suggested: senior project management and planning director Albert Penello explained that Microsoft was initially considering a cloud gaming platform to enable backward compatibility, but he felt it would be "problematic" due to varying internet connection qualities. Xbox Live director of programming Larry "Major Nelson" Hryb did state that users could theoretically use the HDMI-in port on the console to pass an Xbox 360 (or, alternatively, any other device that supports HDMI output, including competing consoles) through Xbox One. This process does generate a small amount of unnoticeable display lag.