play online games. However, Sega found several technical issues that had to be resolved before its Western launch in 1999. Though its Western release was more successful than in Japan, the console was soon outperformed by Sony's PlayStation 2 released in 2000. The PlayStation 2 was the first console to add support for DVD playback in addition to CD-ROM, as well as maintaining backward compatibility with games from the PlayStation library, which helped to draw consumers that remained on the long-tail of the PlayStation. While other consoles of the sixth generation had not anticipated this step, the PlayStation 2's introduction of backwards compatibility became a major design consideration of future generations. Along with a strong game library, the PlayStation 2 went on to sell 155 million units before it was discontinued in 2013, and , remains the best selling home console of all time. Unable to compete with Sony, Sega discontinued the Dreamcast in 2001 and left the hardware market, instead focusing on its software properties. Nintendo's entry in the sixth generation was the GameCube in 2001, its first system to use optical discs based on the miniDVD format. A special Game Boy Player attachment allowed the GameCube to use any of the Game Boy cartridges as well, and adapters were available to allow the console to connect to the Internet via broadband or modem. At this point Microsoft also entered the console market with its first Xbox system, released in 2001. Microsoft considered the PlayStation 2's success as a threat to the personal computer in the living room space, and had developed the Xbox to compete. As such, the Xbox was designed based more on Microsoft's experience from personal computers, using an operating system built out from its Microsoft Windows and DirectX features, utilizing a hard disk for save game store, built-in Ethernet functionality, and created the first console online service, Xbox Live to support multiplayer games. While the original Xbox had modest sales compared to the PlayStation 2 and was not profitable for the company, Microsoft considered the Xbox to have successfully demonstrated their abilities to participate in the console market. Handhelds of the sixth generation Nintendo continued to refine its Game Boy design with the Game Boy Advance in 2001, including its Game Boy Advance SP in 2003 and Game Boy Micro in 2005, all with the ability to link to the GameCube to extend the functionality