Sony launched the first reduced-size PlayStation 2, the SCPH-70000 series, in 2004. The new design radically reduced the volume compared with the original PS2 and moved the power supply outside the case in the first Slim revisions. It also incorporated an Ethernet port as standard for network functions, while removing the 3.5-inch expansion bay used by the official hard drive in the large models. It retained the PlayStation 2 catalogue on DVD-ROM and CD-ROM and much of the compatibility with the original PlayStation. It was a revision of the same platform, not a new generation.