The was released on February 21, 1986 by Nintendo as a peripheral for the Family Computer ("Famicom") console in Japan. It was a unit that used proprietary floppy disks for data storage. It was announced, but never released, for the North American Nintendo Entertainment System. Through its entire production span, 1986-2003, 4.5 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 of RAM for temporary program storage, 8 kilobytes 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 FM synthesis capabilities. The floppy disks used were double-sided, with a capacity of 64 kilobytes per side. 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 Famicom Disk System was capable of running on six C-cell batteries or the supplied AC adapter. 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.
Sharp released the , a composite console of both Famicom and Disk System under license.
While the Disk System was years ahead of its time in terms of a disc-format game console, the system and games both have reliability issues. The drive belt in the drive is a proprietary size, and standard floppy drive belts are too big. In addition, no drive in the U.S. uses that size belt, so replacement belts must be obtained from Japan. 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. The old belts have a habit of breaking or even melting 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 disc 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” floppy disks) to keep dirt out, instead opting to include wax paper sleeves as with the older 5.25” floppies. The only exception to this were certain games that were specially released on blue discs (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.)
Nintendo would hold game score contests, and the mascot was called Disk-kun (Mr. Disk in English). Some of the prizes to these contests included 2 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 disks. Other prizes were a stationary set, and a gold cartridge version of the NES/Famicom Punch-Out!! titles. In the gold version of Punch-Out!!, the final boss 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 Gamecube video game Super Smash Bros. Melee, switching the language to Japanese (via the options menu) would also result in the trophy gallery's NES and Super NES being replaced with a Famicom and Super Famicom, respectively. Additionally, Disk-kun could be unlocked as a trophy via accessing all bonus scores.
In Oh My Goddess! Episode 26, a Famicom Disk System (and presumably a FDS floppy) shows up in the episode as Skuld is making a 10-dimensional scythe.