Virtual Disk Drives¶

FujiNet's most fundamental feature is virtual disk drive emulation. It replaces physical floppy drives by presenting disk image files as real drives to your vintage computer.

How it works¶

flowchart LR
    Computer[Vintage Computer\nAsks for sector data] -->|Peripheral bus| FN[FujiNet ESP32]
    FN --> SD[(SD Card\nLocal images)]
    FN --> NET[(TNFS Server\nNetwork images)]
    SD --> FN
    NET --> FN
    FN -->|Sector data| Computer

Your computer sends disk read/write requests over its peripheral bus (SIO, IEC, etc.) exactly as it would to a physical drive. FujiNet intercepts these requests and serves data from either a local SD card image or a network-hosted image — the computer can't tell the difference.

Supported image formats by platform¶

Atari 8-bitApple IIColeco ADAMCommodore 64CoCo

Format	Description	Notes
`.ATR`	Atari disk image	Most common format
`.XFD`	Transformed image	Older format, fully supported
`.ATX`	Protected disk image	Copy-protected game support
`.CAS`	Cassette tape image	For tape-based programs
`.COM` / `.XEX`	Executable	Load directly without a disk

Format	Description
`.PO`	ProDOS order
`.DO`	DOS 3.3 order
`.DSK`	Generic (order auto-detected)
`.2MG` / `.2IMG`	2IMG with metadata
`.HDV`	Hard disk volume

Format	Description
`.ddp`	Digital data pack (tape)
`.dsk`	Disk image

Format	Description
`.D64`	1541 single-sided
`.D71`	1571 double-sided
`.D81`	1581 high-density
`.T64`	Tape image

Format	Description
`.DSK`	CoCo disk image
`.VHD`	Virtual hard disk

Number of simultaneous drives¶

Platform	Maximum virtual drives
Atari 8-bit	8 (D1: through D8:)
Apple II (SmartPort)	4
Apple II (Disk II)	1–2
Coleco ADAM	4 (2 tape + 2 disk)
Commodore	3 (devices 8, 9, 10)
CoCo	4

Read-only vs. read-write¶

Network-hosted images (from TNFS servers) are always read-only. This protects the shared server files from being corrupted.
SD card images can be mounted read-write — changes you make are saved back to the image file.

Make a working copy

When experimenting with a game or program, copy the image to your SD card first so you can write to it (for save games, configuration, etc.) without affecting the master copy on the TNFS server.

Write-protect control¶

In CONFIG's Hosts & Devices screen, you can toggle the write-protect status of each mounted image using the W key (Atari) or equivalent. A lock icon indicates write-protected status.