Excerpt
The Famicom Disk System was released in February 1986, solely in Japan, and was initially sold for 15,000 yen (equivalent to $100 US at the time). This contrasts to the price of the Famicom in 1983, which was 14,800 yen, about the same price. It primarily consists of two pieces of hardware ? the disk drive itself and the RAM adapter, which connects to the cartridge slot of the Famicom. The disk drive requires another power source, so it supports the use of an AC adapter. Nintendo realized, however, that most power outlets only have two plugs, which would already be used by a television and the Famicom itself, so the FDS can be powered by batteries, too ? six C-batteries, to be precise. The battery slot actually comprises the bulk of the unit, and it's quite light without it. Many pictures show the Famicom on top to the disk drive, though this is not required, as it can be positioned in pretty much any way, as long as the wires from the RAM adapter can be connected to the disk drive. Sharp licensed the technology and issued a two-in-one unit called the Twin Famicom, which also has the benefit of composite video output.
The launch titles for the FDS were simple, mostly stuff already available in cartridge format ? Baseball, Golf, Mahjong, Soccer, Super Mario Bros., and Tennis. The selling piece of the system, though, was Zelda no Densetsu (The Legend of Zelda), an exclusive game that showed off what the hardware could do. In Japan, its slogan was "Yareba Yaruhodo Disk System", which means "If you play, play more, Disk System". The mascot is a little yellow disk with eyes called Disk-kun, and the official term for the format is "disk cards".
So why was the Famicom Disk System released? What were its biggest advantages? The most obvious reason was simple: price. ROM chips were still quite expensive in the mid-80s, especially for a product that was primarily aimed at children. On the other hand, floppy disks were significantly cheaper. After the initial investment of a Disk System, games could be purchased for about 3000 yen, nearly half of what cartridge games cost. Furthermore, many department stores had Disk Writer systems. Blank disks cost 2000 yen, and could be rewritten as long as they weren't broken. Rewriting a game only cost 500 yen, so this was a great deal, especially for children without much money. This unique delivery format also got around Japan's anti-game rental restrictions. Nintendo later used the same concept of the Disk Writer for their Nintendo Power system (unrelated to the American magazine), which they used for Super Famicom and Game Boy games.