Family Computer Disk System
The Family Computer Disk System was a disc add-on for the Nintendo Entertainment System that was only released in Japan despite being announced in America. It used floppy disks which made it very easy for piracy to occur.
Other websites
Video of Disk System features at Powet.TV
More Disk System video at Powet.TV
Video Game Den - Disk System game reviews, screenshots, boxart
Famicom World - More information on the Disk System
N-sider.com - NintendOnline - 4 page article about Nintendo's online history
Storage devices
Nintendo hardware