Nintendo 64DD

The Nintendo 64DD (64DD, Roku Yon Dī Dī?, ロクヨンディーディー) ("DD" being short for "Disk Drive", and originally "Dynamic Drive") is a peripheral for the Nintendo 64 game console. It plugged into the N64 through the EXTension Port on the Nintendo 64's underside, and allowed the N64 to use proprietary 64 MB magneto-optical disks for expanded data storage. Although it had been announced before the launch of the N64, the 64DD's development was lengthy. It was eventually released in Japan when the console was in its twilight years. Scheduled for North American release in 2000, it was a commercial failure, and was never released outside of Japan.