Since the announcement that the Nintendo 64 would use the cartridge format, there has been grumbling about that format's limitations. Nintendo answered that call and announced that they would not be doing a CD-ROM drive, but instead a "bulky" disk drive peripheral that would allow for up to 64 megabytes of storage, split between writable and readable space. The drive was dubbed the 64DD, although a final name has not yet been determined. Games that have been announced to utilize the system include the Legend of Zelda 64 and Mother 3 (the sequel to Earthbound in the US). Since the 64DD will not be ready in time for its release, Zelda will first come out on the cartridge format, being upgraded later by a 64DD disk.

According to Nintendo, the 64DD disks will be bootable (by themselves), or in conjunction with a cartridge game. Expanding existing cartridge games will now be possible, so that a sequel can truly start where the first game left off. The device will read data at the rate of 1 MB per second, approximately the speed of a 6X CD-ROM. The system is planned to include a 4 MB RDRAM upgrade, bringing the total to 8 MB. That will allow games to have large frame buffers and room for custom sound wave tables. A real-time clock will allow games to turn into nighttime when it gets dark outside your window. A good example of a real-time clock used in a game is Sega's Christmas NiGHTS, which changed according to the day of the year.

The size of the disks will be about that of a 3.5" Zip disk, but sealed so younger children won't damage the valuable data inside. Nintendo is addressing the topic of ruggedness by building in features that will make it difficult to stuff anything except 64DD disks into the system's slot.

Writable disks and customizable games will be available to developers with the unit - a feature that's impossible on other systems. The disks can use a varied amount of readable/writable data, anywhere from a split of 38 MB writable and 26 MB readable to the full 64 MB for read-only storage. The DD will read data in bursts, making it impossible to stream full-motion video or audio data using conventional methods.

Well before its release, the 64DD has been criticized by game players because of the limited amount of storage the format handles. The 64 MB capacity is nowhere near the 650 MB of a CD, and even though it is an improvement on the current cartridge format, the games are still not as cheap to produce as CDs. Furthermore, Nintendo is the only company that will produce the disks. One has to wonder how long it will take to produce a 64DD game. Already it has taken Nintendo quite a while to finish existing cartridge projects like Star Fox, Tetrisphere, Ken Griffey Baseball, and Yoshi's Island 2. With Zelda and Mother 3 already being a year away in Japan, and licensees getting development specs now, will the system deliver the promised goods to gamers?