PlayStation is a series of video game consoles created and developed by Sony Interactive Entertainment. The original console in the series, the PlayStation, outsold its main competitor, the N64, and set the standard for optical disc games. The PlayStation 2 is the best-selling and longest running home console to date and has reached over 155 million units sold. Sony continues to develop new consoles and has expanded into the handheld market with the PlayStation Portable (or PSP).