The is a peripheral developed by Nintendo to expand the capabilities of the Nintendo 64 with rewritable magnetic disks and online connectivity. Announced in 1995 before the Nintendo 64's 1996 launch, it faced multiple delays before its release in Japan on December 11, 1999. The "64" references both the Nintendo 64 console and the 64 MB storage capacity of the disks, while "DD" stands for "disk drive" or "dynamic drive". Many games originally planned for the 64DD were instead released as standard Nintendo 64 titles, ported to the more-powerful GameCube, or canceled altogether.
IGN lamented the device as "broken promises" and "vaporware", but described what was launched as "an appealing creativity package" In 1994, Howard Lincoln, chairman of Nintendo of America said, "Right now, cartridges offer faster access time and more speed of movement and characters than CDs. So, we'll introduce our new hardware with cartridges. But eventually, these problems with CDs will be overcome. When that happens, you'll see Nintendo using CD as the software storage medium for our 64-bit system."
In consideration of the 64DD's actual launch price equivalent of about , Nintendo software engineering manager Jim Merrick warned, "We're very sensitive to the cost of the console. We could get an eight-speed CD-ROM mechanism in the unit, but in the under-$200 console market, it would be hard to pull that off." Describing the final choice of proprietary floppy disks instead of CD-ROM, 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." although giving virtually no technical specifications. Computer and Video Games reported unconfirmed specifications, far above what would be actually launched: 4" disk caddy, 150 MB floppy disks, 2.44 Mbit/s speed, 13 ms access, 2-4 MB RAM upgrade, and costing about (US$200).
The 64DD was fully revealed at Nintendo's Shoshinkai 1996 show of November 22–24, 1996, There, Nintendo of America Chairman Howard Lincoln stated that the hardware specifications had been finalized and had its own show booth. Nintendo's Director of Corporate Communications, Perrin Kaplan, made the company's first official launch window announcement for the peripheral, scheduled for late 1997 in Japan. Core Magazine said, "Nintendo representatives insisted the system would be aggressively supported by third parties and Nintendo's internal development teams" with sequels for Super Mario 64 and Zelda 64, and 64DD originals Cabbage and Emperor of the Jungle. Nintendo's list of 64DD developers included Konami, Capcom, Enix, and Rare.
Reportedly, several developers attended the show to learn 64DD development, some having traveled from the US for the 64DD presentation and some having received 64DD development kits.
The event featured Creator, a music and animation game by Software Creations,
Much of the gaming press said the 64DD reveal at Shoshinkai 1996 was not as significant as Nintendo had promised, leaving the public still unaware of the system's software lineup, practical capabilities, and release date. Zelda 64 (eventually released as the cartridge game The Legend of Zelda: Ocarina of Time) was seen as the 64DD's potential killer app in the months following the system's unveiling.
On April 3–4, 1997, Nintendo of America hosted a Developer's Conference in Seattle, Washington, where a surprise overview was delivered by Nintendo Developer Support staff Mark DeLoura about the 64DD. On June 9, 1997, Nintendo and Alps Electric announced their manufacturing partnership for the still tentatively titled