The Nintendo 64DD (Disk Drive) was announced around the release of the main unit. It was to be created in collaboration with Recruit to be an expansion drive that would allow the Nintendo 64 to play disk-based software. The device fit conveniently into an expansion slot located on the underside of the Nintendo 64. The media used in the 64DD came in the form of custom disks that could each hold 64MB of data. The disk-based media was chosen because it was cheaper than standard Nintendo 64 cartridges and therefore more competitive with Sony's CD-ROM based hardware. Furthermore, it was a proprietary media allowing Nintendo to retain its hold on the format and stave off piracy. The unit promised several innovations. The format would have provided players a rewritable media for massive saves and player-customized or downloaded creations as well as the ability to purchase expansion disks for their Nintendo 64 games. The device would have even allowed users to go online using the Randnet DD service. Unfortunately Nintendo was having a difficult enough time struggling to support the Nintendo 64. Then it was faced with having to wait several years for the price of the N64DD technology to decrease. The unit was delayed over and over until it was released in Japan at the tail-end of the Nintendo 64's life. Nintendo ultimately released the unit to save face. It was a market failure beyond the level of the Virtual Boy. Fortunately, it was a learning experience for Nintendo where it had the opportunity to discover and refine several innovations including the internal clock, rewritable media, and the potential of online gaming.