at shoshinkai of 1995, nintendo announced its development of the complementary 64dd, a rewritable magnetic disk based peripheral with several times faster transfer rates and seek time than competing cd-rom consoles. in 1997, nintendo game designer shigesato itoi explained, "cd holds a lot of data, dd holds a moderate amount of data and backs the data up, and [cartridge] roms hold the least data and process the fastest. by attaching a dd to the game console, we can drastically increase the number of possible genres. ... i think we'll make the game on a cartridge first, then ... finish it up as a full-out 64dd game." many nintendo 64 games were developed in a way that depended upon or were expanded by that device. however, after the device's launch had been delayed several years until 1999 and restricted to japan, it was discontinued early as a commercial failure.