Family Computer Disk System
|This article does not cite any references or sources. (June 2007)|
|Type||Video game console add-on|
|Generation||Third generation (8-bit era)|
|CPU||Ricoh 2A03 8-bit processor (MOS Technology 6502 core)|
|Best-selling game||Super Mario Bros.: The Lost Levels|
The Family Computer Disk System (ファミリーコンピュータ ディスクシステム Famirī Konpyūta Disuku Shisutemu , sometimes called the Famicom Disk System, the Disk System, the FDS and the FCD) was released on February 21, 1986 by Nintendo as a peripheral for the Famicom console in Japan. It was a unit that used proprietary floppy disks (called "Disk Cards") for data storage. It was announced, but not released, for the North American/PAL Nintendo Entertainment System. Through its entire production span, 1986–2003, 4.44 million units were sold.
The device was connected to the Famicom deck by plugging a modified cartridge known as the RAM Adapter into the system's cartridge port, which attached via a supplied cable to the disk drive. The RAM adapter contained 32 kilobytes (KB) of RAM for temporary program storage, 8 KB of RAM for tile and sprite data storage, and an ASIC known as the 2C33. The ASIC acted as a disk controller for the floppy drive, and also included additional sound hardware featuring primitive wavetable synthesis and FM synthesis capabilities. The Disk Cards used were double-sided, with a total capacity of 112 KB per disk. Many games spanned both sides of a disk, requiring the user to switch sides at some point during gameplay. A few games used two full disks (four sides). The Disk System was capable of running on six C-cell batteries or the supplied AC adapter. Batteries would usually last five months with daily game play. The battery option was included due to the likelihood of a standard set of AC plugs already being occupied by a Famicom and a television.
In 1986, the disks' 112 KB of storage space was quite appealing. The rewritable aspect of the disks also opened up new possibilities; games such as The Legend of Zelda, Metroid, and Kid Icarus were released to the FDS with a save feature. Many of these titles were subsequently ported to cartridge format and released for the NES a year or two later, with saving implemented via password resume or battery-backed memory.
Hardware versions 
The Disk System's Disk Cards were somewhat proprietary 2.8 in × 3 in (71 mm × 76 mm) 56K-per-side double-sided floppy. These "Disk Cards," as they are officially called, were a slight modification of Mitsumi's "Quick Disk" 2.8 in (71 mm) square disk format which was used in a handful of Japanese computers and various synthesizer keyboards, along with a few word processors. Some of the QuickDisk drives even made it into devices in Europe and North America, though they were somewhat rare. Mitsumi already had close relations with Nintendo, as it manufactured the Famicom and NES consoles, and possibly other Nintendo hardware.
Nintendo's flagship mascot brothers Mario and Luigi make an appearance in the FDS's BIOS. After turning on the system, a "battle" between the two characters would begin over the color scheme of the Nintendo sign and screen border, until a disk is inserted into the FDS.
While the Disk System was years ahead of its time in terms of a disk-format game console, the system and games both have reliability issues. The drive belt in the drive is a proprietary size, since standard floppy drive belts are too large. Until 2004, Japanese residents were able to send their systems to Nintendo directly for repairs/belt replacements, but Nintendo of America and the PAL regions do not service them (as the system was not released in those regions). Due to a flaw in manufacturing, the old belts had a tendency to break, decompose or melt on occasion.
In addition, the disks themselves must be tested and verified to work on both sides, as the FDS disks′ construction can allow dirt to get into the disk, or even for the disk to demagnetize over time. Even one bad sector on a disk will render it unplayable. In an effort to save money on production, Nintendo opted to not use disk shutters (a feature seen on 3.5 in (89 mm) floppy disks) to keep dirt out, instead opting to include wax paper sleeves as with the older 5.25 in (133 mm) disks. The only exception to this were certain games that were specially released on blue disks (which did have shutters).
Also, error messages received when attempting to load a disk are unusually simple, to the point where it is difficult to know what the exact problem is. Most in-game error messages during loading are often displayed as 'Err. ##', with ## being the designated number for the type of error message; the most common ones are Err. 02 (the Disk System's batteries being low on power or with no batteries put in altogether), Err. 07 (Side A and B reversed when trying to load the disk), and Err. 27 ('Disk trouble', usually involving the disk surface itself). However, the error messages themselves consist of little explanation (Err. 27, for example, only give the accompanying message 'Disk trouble') and in most cases within gameplay itself, such as Zelda 2, the error message is not given at all, with only the number code shown.
Square Co., Ltd. had a branch at one point called 'Disk Original Group', a software label that published Disk System titles from Japanese PC software companies. The venture was largely a failure and almost pushed a pre-Final Fantasy Square into bankruptcy. (Final Fantasy was to be released for the FDS, but a disagreement over Nintendo's copyright policies caused Square to change its position and release the game as a cartridge.)
Launch titles 
Nintendo would hold game score contests, and the mascot was called Disk-kun (Mr. Disk or Disk Boy in English). Some of the prizes to these contests included two gold prize disks, one for the game Golf US course, and one for Golf Japan course (not to be confused with the title simply called Golf). These two gold disks had metal shutters on them, like the aforementioned blue Disk Cards. Other prizes were a stationery set, and a gold cartridge version of the Punch-Out!! for the Family Computer. In the gold version of Punch-Out!!, the final opponent was Super Macho Man, before Nintendo used Mike Tyson and Mr. Dream instead in later NES versions.
Many years after the FDS was released, the system and its Disk-kun mascot would be recognized by Nintendo and others. In the Nintendo GameCube video game Super Smash Bros. Melee, switching the language to Japanese (via the options menu) would also result in the trophy gallery's Nintendo Entertainment System and Super NES being replaced with a Family Computer and Super Famicom, respectively. Additionally, Disk-kun could be unlocked as a trophy via accessing all bonus scores.
The background music of the Nintendo GameCube's system menu is a highly slowed-down version of the FDS startup jingle.
In the Oh My Goddess! TV series, a Disk System (and presumably a Disk Card) shows up in episode 26.
The FDS boot up theme is briefly played in Paper Mario: The Thousand-Year Door when Princess Peach inserts a floppy disk into Sir Grodus' computer during the fifth chapter's interlude.
See also 
- Famicom Dojo - Information on Famicom Disk System product codes and video of Disk System features
- Famicom World - More information on the Disk System
- N-sider.com - NintendOnline - 4 page article about Nintendo's online history
- Famicom Disk System - FDS disk copying, writing, and dumping information. Also includes information on Famicom game doctors and related items.