Family Computer Disk System

Overview

The Family Computer Disk System (FDS) is the 1986 disk-based add-on for Nintendo’s Famicom, adding extra RAM, faster saves and enhanced audio. REG-Linux treats it as part of the nes family while tagging it with fds so compatible themes can show dedicated assets.

Supported ROM extensions

.fds, .zip, .7z

Quick reference

• Emulator: RetroArch
• Cores: libretro: fceumm, libretro: Nestopia
• ROM folder: /userdata/roms/fds
• Accepted formats: .fds, .zip, .7z

BIOS

MAME-style cores require the Disk System BIOS (disksys.rom) to be present in bios/:

MD5 checksum	Share file path	Description
ca30b50f880eb660a320674ed365ef7a	bios/disksys.rom	Famicom Disk System BIOS

Keep the filename unchanged so the detection logic works.

ROMs

Place each title under /userdata/roms/fds/<name>.fds/ or store zipped .zip/.7z archives; REG-Linux will list them using the .fds extension. Avoid extracting the ROM files; keep them compressed for the emulator to recognize them.

Emulators

RetroArch (libretro: fceumm / Nestopia)

RetroArch hosts the NES cores, and they expose the FDS options described below. Open the Quick Menu during a game ([HOTKEY] + south button) to access advanced settings or controller mapping.

Standardized options across libretro NES cores: fds.videomode, fds.ratio, fds.smooth, fds.shaders, fds.pixel_perfect, fds.decoration, fds.game_translation.

ES setting name REG-Linux.conf_key	Description => ES option key_value
GRAPHICS API fds.gfxbackend	Choose OpenGL or Vulkan rendering.
AUDIO LATENCY fds.audio_latency	Raise buffer to fix crackling; lower to reduce latency.
THREADED VIDEO fds.video_threaded	Offload rendering for better speed.

libretro: fceumm configuration

ES setting name	Description => Value
global.fceumm_nospritelimit	Remove sprite per line limit.
global.fceumm_palette	Select color palette (default, composite, smooth, etc.).
global.fceumm_ntsc_filter	Enable blargg NTSC filters (RGB/composite).
global.fceumm_sndquality	Raise audio quality (Low/High/Very High).
global.controller1_nes/global.controller2_nes	Choose NES Gamepad, Zapper or Arkanoid paddle.

libretro: Nestopia configuration

ES setting name	Description => Value
global.nestopia_nospritelimit	Remove sprite per line limit.
global.nestopia_palette	Choose color palette.
global.nestopia_blargg_ntsc_filter	Toggle NTSC filters.
global.nestopia_overclock	Overclock the CPU (off/2x).
global.nestopia_select_adapter	Force 4-player adapter mode (NTSC/Famicom).

Controls

FDS games map to the default REG-Linux Retropad overlay for NES controllers:

Troubleshooting

• Ensure /userdata/roms/fds/ contains .fds folders or zipped archives, and that the BIOS disksys.rom is installed.
• Switch between NES cores if a game behaves differently; some titles prefer one core’s timing.