Rusty Backup

Cross-platform GUI tool for backing up, restoring, and inspecting vintage computer disk images. The name is a play on words — both referencing the Rust programming language and the rusty vintage machines we're preserving.

Primary users are retro computing enthusiasts archiving CF/SD cards, IDE/SCSI drives, and floppy images from DOS, Windows 9x, early Linux, classic Mac OS, and Apple II / IIgs systems.

Licensed under AGPL-3.0. See PROJECT-SPEC.md for the full design specification and docs/ for deep-dive topics.

Installation

Rusty Backup ships as a single self-contained binary per platform.

1. Grab the latest build for your OS from the GitHub Releases page.
2. Drop the binary where you want it:
   • Windows — run Setup.exe for the installed experience (Start-Menu shortcut, "Add/Remove Programs" entry, optional file-association registration, rb-cli on PATH), or extract the portable ZIP and run rusty-backup.exe directly. Either install can self-update in place from within the About / Update UI; existing portable-ZIP users can run Setup.exe once to gain the Start-Menu / ARP integration without re-downloading later updates.
   • macOS — open the DMG and drag Rusty Backup.app into /Applications.
   • Linux — chmod +x rusty-backup-*.AppImage and launch it.
3. Raw physical disks require elevated privileges (admin on Windows, root on Linux, an authorisation prompt on macOS). Working with image files on disk does not.

To build from source: cargo build --release. See CLAUDE.md for the full build matrix.

The rb-cli headless CLI

The release artifacts also include rb-cli, the scriptable counterpart to the GUI. Same engine, no eframe dependency, designed for shell pipelines and automated build farms.

rb-cli new disk.dsk --fs hfs --size 800K --name "My Disk"
rb-cli put disk.dsk ./Finder /System/Finder --type FNDR --creator MACS
rb-cli ls  disk.dsk /System
rb-cli cp  floppy.adf / harddisk.hda@1 /Floppies/d01/ -r   # consolidate an image onto a HD
rb-cli tar irix.img@1 / irix.tar.gz   # archive a case-sensitive volume (keeps case + symlinks)
rb-cli untar disk.hda src.tar.gz /   # import an archive's contents INTO an image (skips ._* + unstorable names)
rb-cli get backup.zip /unix ./unix --inside disk.img   # extract from a RAW disk inside a .zip
rb-cli fsck disk.dsk --checkonly
rb-cli inspect disk.hda
rb-cli backup /dev/disk3 ./backups --format chd --checksum sha256
rb-cli restore ./backups/my-backup ./restored.img
rb-cli batch script.json --dry-run
rb-cli new-x68k-hdd hdd.hdf --size 16M --system-disk human68k.dim
rb-cli new-x68k-hdd c.hdf --size 32M --variant scsi --system-disk human68k.dim \
                          --boot-sector-donor hd0.hds      # zero manual steps, your donor
rb-cli new-x68k-hdd c.hdf --size 32M --variant scsi --system-disk human68k.dim \
                          --builtin-boot-sector            # zero manual steps, no donor needed
rb-cli new-sgi-hdd irix.img --size 50M                     # IRIX SGI dvh + EFS root HDD
rb-cli new-sgi-cdrom irix.iso --size 600M                  # IRIX EFS CD-ROM (slot-7 SYSV, mount -t efs)
rb-cli put irix.img@1 ./bstoolbox /bstoolbox               # populate its EFS root partition
rb-cli mac-scsi-bless mac.hda                              # install Apple SCSI driver + DDR
rb-cli mac-scsi-bless mac.hda --driver-from donor.hda      # use a donor disk's driver verbatim
rb-cli make-bootable disk.dsk --boot-from "System 7.0 HD.dsk"  # auto: apply only what's missing to boot
rb-cli make-bootable mac.hda --dry-run                     # preview: detect kind + missing pieces

Shell completions for bash / zsh / fish / PowerShell:

rb-cli install-completions          # auto-detects $SHELL
rb-cli completions zsh > _rb-cli    # emit-to-stdout for packagers

Full verb-by-verb reference: docs/cli-reference.md (regenerated from cargo run --example generate_cli_reference). Open CLI follow-ups (and everything else still to do) are tracked in docs/OPEN-WORK.md.

rb-cli-mini for MiSTer FPGA (armv7)

rb-cli-mini is the MiSTer-specific build of rb-cli: a slim variant cross-compiled for the FPGA's Intel Cyclone V / Cortex-A9 SoC (armv7-unknown-linux-gnueabihf, glibc 2.31 baseline from the Buildroot rootfs). It excludes the GUI (eframe / egui / rfd), the optical-disc stack (opticaldiscs / cd-da-reader), and the update checker's reqwest client — but keeps CHD support via the upstream libchdman-rs armv7 prebuilt, so .chd images work inline on the device.

The desktop release builds use the full feature set; only the MiSTer artifact runs --no-default-features --features chd,pure-zstd,remote (CHD via the C prebuilt; zstd via the pure-Rust bit-exact backend, since a cross build won't link C libzstd; remote for the network daemon — see rb-daemon below).

# Cross-compile for MiSTer (armv7-unknown-linux-gnueabihf):
cargo install cross --git https://github.com/cross-rs/cross --locked
cross build --bin rb-cli --release \
            --target armv7-unknown-linux-gnueabihf \
            --no-default-features --features chd,pure-zstd,remote

# Strip + deploy. The release tarball ships the binary as `rb-cli-mini`;
# do the local rename here too so the on-MiSTer filename matches the
# downloads-page artifact (and so completion lookups land in the right
# spot — see below).
arm-linux-gnueabihf-strip target/armv7-unknown-linux-gnueabihf/release/rb-cli
scp target/armv7-unknown-linux-gnueabihf/release/rb-cli \
    root@mister.local:/media/fat/Scripts/rb-cli-mini

The repo's Cross.toml pins the cross-compile Docker image to cross-rs's Ubuntu 20.04 / GCC 9.4 / glibc 2.31 build (at a verified SHA digest) so the binary links against the same glibc + libstdc++ baseline as both the MiSTer Buildroot rootfs and the upstream libchdman-rs armv7 prebuilt — symbols line up without any version drift.

CI ships a prebuilt rb-cli-mini-armv7-linux-<version>.tar.gz as part of every release; grab it from the Releases page if you don't want to set up the cross toolchain locally.

What's in the MiSTer build:

• Every filesystem operation (ls, put, get, tar, untar, rm, mkdir, fsck, resize, expand, chmeta, bless, …) on FAT, NTFS, exFAT, HFS, HFS+, ext, AFFS, PFS3, SFS, ProDOS, Human68k, ADFS, etc.
• inspect, backup, restore for Raw, VHD, QCOW2, VMDK, Zstd, the four floppy container formats, and CHD.
• floppy convert (XDF / HDM / DIM / D88, single-file and bulk) — the X68000 workflow runs inline on the device.
• Partition table editing (partmap), backup-folder operations.
• shrink, grow .chd, single-file CHD backups — all work.
• The rb-daemon network daemon (serve) — host this device's images and disks on the LAN so the desktop app can browse/back up/restore them over rb://. Installs from the Scripts menu; see below.

What's excluded (operations exit with a clear "this binary was built without the optical feature" message):

• optical verb (rip / disc browse / extract via the OS optical-drive layer — the MiSTer has no optical drive attached).
• GUI windows and the update-checker self-replace UI (only meaningful for the desktop binary).

Full background and the feature matrix live in docs/mister_cli.md.

Run this device as a network daemon (rb-daemon)

The MiSTer build can run as a small network daemon so the desktop Rusty Backup app reaches into the MiSTer over your LAN — browse the SD card and the disk images on it, copy files in and out, and back up / restore whole disks — without pulling the card. It works like mrext's Remote: one entry in the Scripts menu, auto-start on boot once enabled.

Install it from the rb-cli-mini release tarball (it now bundles the daemon shim + installer):

# On the MiSTer (or over SSH), from the unpacked tarball:
./install.sh

That drops two files onto the SD card:

• /media/fat/Scripts/rb-cli — the program (no .sh, so it is not a second Scripts-menu entry).
• /media/fat/Scripts/rb-daemon.sh — the only menu entry: open it to bring up the daemon console.

Then open rb-daemon from the MiSTer Scripts menu. The console shows whether the daemon is running, whether it auto-starts on boot, and the IP:port other machines connect to, with these actions:

• Start Now / Stop Now — run or stop the daemon immediately.
• Install Autostart — start it now and launch it on every boot.
• Uninstall Autostart — stop launching it on boot (a running daemon keeps running).

Everything is scriptable too — no console needed:

rb-cli serve service install     # enable on boot + start now
rb-cli serve service status      # ACTIVE/INACTIVE, autostart, IP:port
rb-cli serve service stop        # stop the running daemon
rb-cli serve service uninstall   # remove the boot entry

Defaults (editable in /media/fat/Scripts/rb-daemon.ini) serve the whole /media/fat card on 0.0.0.0:7341, writable. From the desktop, connect to rb://<mister-ip>:7341/. The daemon design lives in docs/remote_transfer_plan.md.

Bootable backup appliances (boot the metal, no host OS)

For machines too old or too bare to run the desktop app, the same engine ships as bootable media you run on (or beside) the vintage box:

• Linux appliance — a minimal Buildroot Linux that boots straight into the rb-cli backup/restore menu (on a VGA monitor or a serial console) with the static rb-cli baked in. One hybrid ISO boots from a CD-ROM or a USB stick / CF card (dd the same file onto the device). The kernel carries a broad vintage-hardware driver set — ISA / PCI / PC-Card NICs, SCSI HBAs, bare-486 / VL-Bus + PCI IDE, Multi-I/O serial & parallel, parallel-port ZIP, USB storage — so it sees the disks and cards in a 486/Pentium-class machine out of the box. What's baked in, how to make an unusual card work (ISA modprobe io=/irq= recipes), and how to rebuild the kernel for more are in docs/appliance_hardware_support.md; build/boot overview in docs/linux_486_appliance.md.
• cb-dos — the DOS-native lane: a FreeDOS floppy / CD that images disks with a hand-written C tool over BIOS int 13h, for boxes where even a minimal Linux is too heavy. See docs/cb_dos.md.

Both build from the repo (buildroot/, crusty-backup/).

Usage

The app has five tabs:

• Backup — pick a source (physical device or image file), choose a destination folder, pick an output format and checksum type, and start. Each backup is written as a folder containing metadata.json, the partition table sidecar (mbr.json / gpt.json / apm.json / RDB / SGI), and either one compressed file per partition (Zstd / Raw / per-partition VHD) or a single <backup-name>.chd disk image that chdman info opens and MAME loads directly (CHD output). The single-file CHD also serves as the unit edit mode operates on, so changes flow back into a CHD that any CHD-aware tool can still read.
• Restore — pick a backup folder and a target device or image file. Partition sizes can be left at original, shrunk to the filesystem minimum, or set to a custom value; the filesystem is expanded in place when the restored partition is larger than the minimum. Alignment (DOS/cylinder, 1 MB, or custom) is preserved from the source by default. A top-level "Add free space for in-OS expansion" toggle pads the target image so the guest OS can extend partitions there after boot — see the Disk expansion workflow section below.
• Inspect — pick any supported source and browse the partition table, filesystem info, and file listings. Several actions live here:

  • Browse filesystem contents read-only (per partition).

  • Edit Partition Table… to add / resize / delete / retype partition entries on raw disks, image files, and devices. Writers cover MBR, GPT, APM, SGI, and RDB-bootable-flag.

  • Resize Partitions… for in-place partition data moves with filesystem-side patching.

  • Add Partition… as a streamlined entry into the editor when trailing free space exists, pre-filled per partition-table type.

  • Expand Image… to grow a raw, VHD, or CHD image with trailing zero-padding so you have room for new partitions.

  • Export Disk Image… to write VHD (fixed or dynamic), QCOW2, VMDK, Raw, 2MG, WOZ, DC42, HFV, or CHD (whole-disk or per-partition) — see docs/vhd-export.md.

  • Convert Floppy Container… to convert between the four X68000 / PC-98 / FM-7 floppy wrappers (XDF, HDM, DIM, D88) one file at a time. Bulk folder conversion lives in the existing Bulk Convert dialog, which now lists the same four formats as output targets.

  • Check (fsck) on classic HFS, HFS+, AmigaDOS (Disk Validator), and SGI EFS, with Repair that uses replica blocks + lost+found where supported.

  • Defragment… on Human68k (X68000) partitions: repack the volume so files are stored contiguously, reclaiming holes left by deleted files (also rb-cli repack).

  • Build a Sharp X68000 HDD from scratch via the shell: rb-cli new-x68k-hdd out.hdf --size 16M --system-disk donor.dim (SASI default, --variant scsi available) — emits a self-bootable HDD with the Sharp IPL signature, X68K partition table, and a full Human68k system clone from a donor .dim / .D88 / .xdf / .hdm floppy. Boots clean in MAME x68000 -sasi / x68030 -hard. Add --boot-sector-donor hd0.hds (the well-known 100 MB Sharp/Keisoku Giken SCSI HDD image, file size 104,857,600 bytes, widely mirrored on retro-archive sites under that exact filename) plus --variant scsi to overlay the donor's Sharp partition boot sector — the HDD then self-boots straight to C:> on every power-on with no manual SWITCH.X step. Any --size from 1 MiB to ~512 MiB works: the builder patches the donor's embedded BPB with the output partition's actual FAT geometry, so the donor boots from your sized HDD regardless of how the donor itself was sized.

  • Make a classic-Mac SCSI disk bootable via the shell: rb-cli mac-scsi-bless mac.hda installs an Apple SCSI driver and a valid Driver Descriptor Record into an APM disk so a Macintosh ROM (e.g. Quadra 800) registers the drive over SCSI. Uses a bundled known-good driver by default, or --driver-from donor.hda to copy a donor disk's driver verbatim. Operates in place; partition data never moves, and it is idempotent. (This registers the driver so the ROM can read the disk — it does not change HFS boot-block behavior.) Verified against the real Quadra 800 ROM in QEMU -M q800.

  • Make a Mac disk bootable — rb-cli make-bootable disk.img [--boot-from "System 7.5.3 HD.dsk"] (or the Inspect tab's Make Bootable... button) auto-detects what the disk is and applies only what it's missing:

    • a flat .hfv/.dsk (BasiliskII / SheepShaver / Mini vMac, e.g. a customized infinite-mac disk) — boot blocks + blessed System Folder, kept flat (no APM wrapper added);
    • a full APM disk (an infinite-mac "device image" with DDR + map + drivers, or any Mac SCSI disk image) — a SCSI driver + DDR (bundled, or --driver-from donor) if absent, then boot blocks on the Apple_HFS partition + bless, leaving the DDR / map / drivers untouched.

    Boot blocks are never synthesized — they're copied verbatim from a --boot-from donor that already boots that System, so they stay version-matched. The operation is idempotent (--dry-run previews it). The lower-level pieces are also available on their own: rb-cli put IMG[@N] --boot-from DONOR, rb-cli bless set, and the browse-view Boot Blocks... / Bless Folder buttons.

  • Edit mode on FAT, NTFS, exFAT, ext, HFS, HFS+, AFFS, PFS3, SFS, ProDOS, Apple DOS 3.3, MacPlus MFS, EFS, UFS, CP/M (multi-DPB), Human68k, and XFS (v4 + v5): stage create-file / new-folder / drag-and-drop / delete edits, then Apply atomically with snapshot rollback on error.

• Optical — browse and extract files from CD/DVD images and physical optical drives. Supports ISO9660, Joliet, Rock Ridge, and HFS hybrid discs. Re-opens automatically when the underlying disc changes.
• Archives — browse and extract classic Macintosh archives. Auto-detects StuffIt 1-5 (.sit, .sea self-extracting), Compact Pro (.cpt), MAR (.mar, read + write), and BinHex (.hqx) wrappers around any of them. Pick an archive, browse the entry tree (name / type / creator / size / codec), tick the entries to keep, and extract to a folder in your choice of fork-preserving container — BinHex, MacBinary, AppleDouble, or raw data + .rsrc sidecar. Export a file or folder back out as .sit, .sit.hqx, .hqx, or .mar. Single-entry archives whose payload is itself a disk image (DiskCopy 4.2, raw HFS, raw HFS+) get a one-click "Mount in new Inspect tab" handoff. rb-cli archive list / archive extract / archive create (formerly sit, still accepted) is the scriptable counterpart.

Most popups (Resize Partitions, Edit Partition Table, Export Disk Image, restore-tab partition list) use a shared Size Mode radio set (Original / Minimum / Custom / Fill) and a Current → After disk-layout bar pair so the planned outcome is always visible before you commit.

VHD export is available from the Inspect tab: produce either a whole-disk .vhd (partition table plus all partitions with their gaps) or per-partition .vhd files, ready to mount in VirtualBox, Hyper-V, or QEMU. See docs/vhd-export.md.

Disk expansion workflow

Rusty Backup can grow an existing image so its guest OS sees a bigger disk. This is useful for any filesystem the OS can expand at runtime — XFS being the motivating case (xfs_growfs can only ever grow up to the partition boundary, never the disk boundary), but the same workflow works for ext, NTFS, FAT, HFS+, exFAT, btrfs, etc.

Open an existing image and add trailing free space:

1. Open the image in the Inspect tab. Any backup, raw disk image, VHD, or CHD works.
2. Click Expand Image… in the toolbar. Enter how much MiB to add and click Expand. Raw/VHD images grow instantly via set_len; CHD images re-encode in a background worker (the CHD hunk layout is fixed at creation, so there's no in-place grow).
3. Click Re-inspect to refresh the partition list. The new trailing region appears as a gray "Free" segment in the Disk layout bar.
4. Either:
   • Click Add Partition… to allocate the free space as a new partition (defaults are pre-filled per partition-table type — XFS for SGI, 0x83 for MBR, Linux Filesystem GUID for GPT, Apple_HFS for APM), or
   • Click Edit Partition Table… and bump the last partition's size via the Size Mode radios.
5. Boot the guest OS and run the filesystem's native grow tool (xfs_growfs /mountpoint, resize2fs, Disk Management's Extend Volume, IRIX fx + xfs_growfs, …).

Same workflow during a restore (useful when the target physical disk is larger than the source):

1. Restore tab → pick the backup and an image-file target. (The feature is disabled for device targets — physical disk size is fixed.)
2. Tick Add free space for in-OS expansion and enter MiB.
3. Pick a mode:
   • Leave as unpartitioned free space (recommended) — partition table stays unchanged; the guest OS uses its native partitioner plus xfs_growfs (or equivalent). Works for any filesystem on any OS.
   • Extend last partition automatically — the last partition is sized to absorb the new free space during restore. After restore, only the filesystem-side grow tool is needed.
4. The Current / After disk-layout bar pair shows the planned result before you commit.

Note on visualisations: the Disk layout bar appears in five places (Inspect, Restore, Resize Partitions, Edit Partition Table, Export Disk Image) so what you see is always what'll be written. Partition colours cycle through a stable palette; tiny partitions (≤ ~1 MiB) get a minimum-width pip so GPT/APM disks with many small partitions stay readable.

Compatibility

Image / backup formats

Format	Extension	Read as source	Write as backup	Notes
Raw	.img, .raw, .hda	Yes	Yes	Sparse zero-skipping; optional splitting
Fixed VHD	.vhd	Yes	Yes	512-byte footer; also used for VHD export
Dynamic VHD	.vhd	Yes	Yes	Sparse, allocate-on-write
QCOW2 (QEMU)	.qcow2	Yes	Yes (create / edit)	v2 + v3
VMDK (VMware)	.vmdk	Yes	Yes (create / edit)	Flat and monolithic-sparse
Zstd stream	.zst	Yes	Yes	Good general compression, splittable
CHD (MAME)	.chd	Yes	Yes	Native (MAME's CHD core is bundled — no external chdman needed)
Norton Ghost	.gho, .ghs	Yes	No	File-aware FAT/NTFS browse, sector + spanned sets, Ghost 7.5, password-protected images decrypted automatically
WinImage	.imz	Yes	No	Including password-protected archives
ZIP (raw disk)	.zip	Yes	No	A RAW disk image inside a plain ZIP. Auto-picks the disk entry (--inside NAME to choose one of several); inflated sparsely to a temp file at open, so a mostly-empty multi-GB image only uses its real content. Picker-visible but not OS-associated
BasiliskII HFV	.hfv	Yes	Yes	Flat classic-HFS volume (≤ 2047 MB) for 68k Mac emulators
Apple 2MG	.2mg	Yes	No	Apple II / IIgs disk images
Apple II DSK	.dsk, .do, .po	Yes	No	DOS-order, ProDOS-order, and auto-detect sector orderings
Disk Copy 4.2	.dc42, .image	Yes	No	Classic Mac floppy images
Apple DMG	.dmg	Yes (raw/UDRW)	No	Uncompressed DMGs only
WOZ	.woz	Yes	Yes (export)	Apple II 5.25" and 3.5"; WOZ2 writer regenerates a clean image
Amiga ADF / HDF	.adf, .hdf	Yes	Yes (raw)	Floppy + hard-disk images. RDB partition tables parsed. Arculator-wrapped .hdf (Acorn) auto-detected.
Gzip-wrapped	.adz, .hdz, .gz	Yes	.adz/.hdz only	Any gzip-wrapped disk image, transparently decompressed at open. .adz/.hdz are the editable Amiga floppy/HDD wrappers; a bare .gz (e.g. a .pdi.gz Alto/Pilot pack or a gzipped raw image) is read-only.
Atari MSA	.msa	Yes	No	Magic Shadow Archiver — Atari ST 720K / 800K / 1.44MB floppy
CPCEMU DSK / EDSK	.dsk	Yes	No	Amstrad CPC / PCW / Einstein / Oric CP/M floppies
Commodore disk	.d64, .d71, .d81, .d80, .d82	Yes	Yes (in-place edit)	1541 / 1571 / 1581 + PET 8050 / 8250 (IEEE-488) flat sector dumps for the C64 / C128 / C16 / VIC-20 / PET cores. Read/browse/extract + add/delete persist back into the image (bidirectionally cross-validated against the c1541 / Python d64 reference).
Commodore GCR	.g64, .g71	Yes (decode)	No	Raw 1541 / 1571 GCR track images (preservation-grade). Decoded to flat sectors so the CBM engine can read them; the .g71 side-1 mapping is validated against a real VICE c1541 image.
Atari disk	.atr, .xfd	Yes	Yes (in-place edit)	8-bit Atari (400/800/XL/XE) disk images for the Atari800 core. .atr = 16-byte header + sector body; .xfd headerless. Read/browse/extract + add/delete on the Atari DOS 2 volume.
CoCo disk	.dsk, .jvc, .vdk	Yes	Yes (in-place edit)	Tandy Color Computer (CoCo2 / CoCo3 cores) raw 35- / 40-track sector dumps. Headerless flat body (length a multiple of 256). Auto-detects the volume's filesystem: RS-DOS / Disk BASIC (flat granule FS) or OS-9 / NitrOS-9 RBF (hierarchical). Read/browse/extract + add/delete on both.
Acorn DFS disk	.ssd	Yes	Yes (in-place edit)	BBC Micro / BBC Master / Acorn Electron (MiSTer BBCMicro / AcornElectron cores) single-sided floppy. Flat 40-track (100K) / 80-track (200K) sector dump in logical order. Read/browse/extract + add/delete on the Acorn DFS catalogue. (Track-interleaved double-sided .dsd is a follow-up.)
Sharp D88	.d88	Yes	Yes (convert + in-place edit)	X68000 / PC-88 / PC-98 / MSX / FM-7 sparse track-table container. Add/delete/mkdir on the contained Human68k FAT volume persist back into the container (decode -> edit -> re-encode).
X68000 XDF	.xdf	Yes	Yes (convert + in-place edit)	Raw headerless X68000 floppy dump; geometry inferred from size. In-place file add/delete/edit supported.
X68000 HDD	.hda, .hdf, .hds, .ima	Yes	Yes (in-place edit + resize + defrag repack)	Sharp SASI/SCSI hard-disk images; X68k partition table + Human68k FAT12/16. Read/browse/extract + add/delete/mkdir + in-place FS grow/shrink + contiguous repack (SHARP/KG big-endian BPB & FAT). Geometry auto-detected: SCSI X68SCSI1 (table @ 0x800, 1024-byte sectors) and SASI (table @ 0x400, 256-byte sectors, incl. custom-IPL game disks).
PC-98 HDM	.hdm	Yes	Yes (convert + in-place edit)	DiskExplorer raw headerless floppy dump (byte-identical to XDF). In-place file add/delete/edit supported.
DiskExplorer DIM	.dim	Yes	Yes (convert + in-place edit, DIFC)	DIFC 256-byte header + payload; generic 256-byte-header fallback for IBM XDF DIM on read. Add/delete/edit persist back into the container.
Xerox Alto pack	.pdi, .bfs, .copydisk, .altodisk	Yes	Yes	Diablo 31/44 disk packs for the Xerox Alto. .pdi = PARC Disk Image (a flat, self-describing, label-inclusive container designed as the recommended emulator format); .bfs / .copydisk / .altodisk = period CopyDisk streams, imported transparently. Detected by magic, surfaced as a single browsable Alto BFS volume. Browse + extract + add/delete + resize; edits save as PDI.
Salto disk	.dsk	Yes	Yes	Salto Alto-II emulator "cooked" Diablo-31 image ([pageno][header][label][data] per sector). Byte order auto-detected (Salto-native little-endian or big-endian); export writes Salto-native little-endian so the result loads in the emulator. Same Alto BFS content as the other Alto packs.
ContrAlto2 Diablo	.dsk	Yes	No	ContrAlto2 / Bitsavers Diablo-31 pack ([dummy][header][label][data], little-endian, sector-interleaved) — same size as a Salto .dsk but distinguished by content; sectors placed by their header disk address. Read as an Alto BFS volume.
Trident pack	— (raw, size-detected)	Yes	Yes	Trident T-80 / T-300 pack image (ContrAlto2 / dorado layout: [dummy][header][label 10w][data 1024w] per sector, little-endian, 2048-byte pages, physical sector interleave). The same Alto file system (TFS) on Trident hardware; recognized by the exact T-80 (~76 MB) / T-300 (~285 MB) size, surfaced as an Alto BFS volume. Validated against ContrAlto2's real Spruce print-server T-300 pack.
Xerox Pilot/Cedar volume	.pdi (fsFamily=2)	Yes	Yes (create / add file)	D-machine Pilot/Cedar filesystem in a PARC Disk Image. Physical/logical volume roots, subvolume table, VAM, run-table files; both file-ID generations (32-bit Cedar nucleus / 80-bit original Pilot via flags bit 2). Surfaced as a read-only Pilot/Cedar volume in the GUI; blank-volume + add-file via pilot_probe. See docs/ PARC specs.
Dwarf 6085 disk	.zdisk, .zdelta	Yes	No	Dwarf "Draco" 6085/Daybreak emulator rigid-disk image — a zlib stream of label-inclusive Pilot sectors (10-word label + 256-word data; the 6085/IOP stores labels byte-swapped, normalized on read). Opens as a read-only Pilot/Cedar volume; lists and extracts files. The disks shipped with Dwarf (ViewPoint 2.0, XDE 5.0) are the real Pilot volumes our reader was validated against.
Raw physical disk	—	Yes	Yes (restore target)	CF/SD/USB/HDD/SSD — see below

"Yes (convert)" means the format isn't a backup wrapper but is fully round-trippable via the Convert Floppy Container… dialog and rb-cli floppy convert — useful for moving images between MiSTer cores, real hardware utilities, and emulators that each prefer a different floppy container.

Filesystems

All listed filesystems support browsing in the Inspect tab and are preserved intact on backup/restore. "Shrink" means the filesystem can be safely compacted to its minimum size during backup and re-expanded during restore or VHD export. "Edit" means create / delete / drag-and-drop via the inspect-tab Edit Mode.

Filesystem	Browse	Edit	Shrink / expand	fsck	Notes
FAT12	Yes	Yes	Yes	—	Apple II SuperDrive, DOS floppies
FAT16	Yes	Yes	Yes	—	DOS / Windows 3.x / 9x
FAT32	Yes	Yes	Yes	—	Windows 95 OSR2+ through XP, vintage Linux
exFAT	Yes	Yes	Yes (in-place + defragmenting clone)	—	Modern removable media (e.g. MiSTer SD cards). In-place resize trims trailing free space; the defragmenting clone (Compact Space toggle / shrink-to-minimum) repacks allocated clusters into a fresh, smaller volume, so a fragmented card backs up to ~its real data size.
NTFS	Yes	Yes	Yes (in-place + defragmenting clone)	—	Windows NT / 2000 / XP. In-place resize trims trailing free space; the defragmenting clone (Compact Space toggle / shrink-to-minimum) repacks into a fresh, smaller NTFS volume (from-scratch clean-room formatter, validated to mount under ntfs-3g). Create blank volumes with rb-cli new --fs ntfs (selectable --cluster-size / --sector-size, 512 B–2 MiB clusters); the defragmenting clone inherits the source volume's cluster and sector size.
ext2 / ext3 / ext4	Yes	Yes	Yes	—	Early Linux installs onward
HFS (Mac OS Standard)	Yes	Yes	Yes	Yes (check + repair: replica copy, bitmap fixup, lost+found for orphans)	Classic Mac OS 68k / early PowerPC. Includes block-size expansion via clone (Expand HFS Volume…).
HFS+ / HFSX	Yes	Yes	Yes (defrag clone)	Yes (check + repair)	Mac OS Extended; hardlink resolution.
btrfs	Yes	No	No	—	Modern Linux; read-only browse
ProDOS	Yes	Yes	Yes	—	Apple II / IIgs
CBM DOS (1541 / 1571 / 1581 / 8050 / 8250)	Yes	Yes	— (floppy, fixed geometry)	—	Commodore C64 / C128 / C16 / VIC-20 / PET. PETSCII names, bit-set-is-free BAM, linked-sector files. .d64 / .d71 / .d81 / .d80 / .d82; .g64 GCR decoded to sectors.
Atari DOS 2 (2.0S / 2.5)	Yes	Yes	— (floppy, fixed geometry)	—	Atari 8-bit (Atari800 core). VTOC@360 (bit-set-is-free), 64-file directory, linked-sector files. Single + enhanced density .atr / .xfd.
RS-DOS (CoCo Disk BASIC)	Yes	Yes	— (floppy, fixed geometry)	—	Tandy Color Computer (CoCo2 / CoCo3 cores). Granule allocation table on track 17, 72-file directory, granule-chain files. Raw 35- / 40-track .dsk / .jvc. Read/extract + add/delete bidirectionally cross-validated against an independent clean-room reader/writer derived from the toolshed libdecb semantics.
OS-9 / NitrOS-9 RBF	Yes	Yes	— (floppy, fixed geometry)	—	Tandy Color Computer (CoCo2 / CoCo3 cores) and Dragon. Hierarchical Unix-like FS: LSN-0 identification sector, per-file/dir 256-byte file descriptors, segment-list extents, allocation bitmap (set-bit = allocated). Raw .dsk / .vdk. Read/extract + add/delete (incl. subdirectories) cross-validated byte-exact against an independent clean-room RBF reader on real NitrOS-9 toolshed disks.
DragonDOS	Yes	Yes	— (floppy, fixed geometry)	—	Dragon Data Dragon 32/64 (and CoCo running DragonDOS), MiSTer Dragon core. Directory track 20 (backup on 16), one's-complement geometry signature, sector bitmap (set-bit = free), 25-byte directory entries with header + continuation extent blocks. Raw single- / double-sided 40-track .dsk. Read/extract + add/delete cross-validated byte-exact against an independent clean-room reader/writer and against real third-party DragonDOS disks (empty + a populated 9-file disk).
Acorn DFS	Yes	Yes	— (floppy, fixed geometry)	—	BBC Micro / BBC Master / Acorn Electron (MiSTer BBCMicro / AcornElectron cores). Flat-catalogue FS in sectors 0–1: 12-char disc title, up to 31 contiguous files in descending start-sector order, single-character directory namespaces, 18-bit load/exec/length. Single-sided .ssd (40-/80-track). Read/extract + add/delete bidirectionally cross-validated byte-exact against an independent clean-room DFS reader/writer (locked files, non-$ directories, real load/exec addresses all round-trip).
Human68k (FAT12 / FAT16)	Yes	Yes	Yes (HDD in-place grow + shrink, plus defragmenting repack)	—	Sharp X68000. SASI/SCSI hard disks use a Sharp/KG big-endian BPB + big-endian FAT; floppies use standard little-endian FAT. Shift-JIS 18.3 filenames. Shrink stays above the FAT16 floor. rb-cli repack / the Inspect-tab "Defragment…" button repack the volume contiguously, reclaiming holes left by deleted files.
AFFS (OFS / FFS)	Yes	Yes	Yes (in-place; bm_pages only)	Yes (Amiga Disk Validator)	Amiga DOS\0..DOS\7. In-place resize relocates root + bitmap pages; refuses on bm_ext-chain volumes or when allocated data would be clobbered.
PFS3 / PDS3 / muFS	Yes	Yes	Yes (in-place + defragmenting clone)	—	Amiga PFS3 family. Shrink refuses to truncate live data; clone path packs the volume for genuinely smaller targets.
SFS (Smart File System)	Yes	Yes (single-leaf btree)	Yes (in-place trim/grow)	—	Amiga SFS\0 / SFS\2.
SGI EFS	Yes	Yes	Yes (in-place grow + conservative + aggressive shrink)	Yes (check + repair: replica copy, bitmap fixup, lost+found)	IRIX < 6.0. Aggressive shrink renumbers inodes into low CGs.
SGI XFS (v4 / v5)	Yes	Yes (v4 only; v5 editing pending)	Grow via "Add free space" + in-OS xfs_growfs; shrink via clone-into-fresh is planned (see docs/OPEN-WORK.md §2.2)	Yes (R1-R8 repair pipeline; v4 oracle-validated)	IRIX 6.x and Linux. xfs_repair-clean writes.
Alto BFS / TFS	Yes	Yes	Yes (resize)	—	Xerox Alto Basic File System on Diablo 31/44 packs and the same file system on Trident T-80/T-300 (TFS) — one codec parameterized by page size (512 vs 2048 B), label shape (8- vs 10-word), and disk-address width (1- vs 2-word). Flat SysDir namespace, leader pages, page-chain files, and out-of-band sector labels (the file structure lives in the labels, not the data area). Browse + extract + add/delete + resize; opened from .pdi / .bfs / .copydisk / .altodisk / Salto .dsk / Trident pack images (edits save as PDI). Diablo validated against every CopyDisk pack in the CHM Xerox PARC archive + the Salto/dorado disks; Trident validated against ContrAlto2's real Spruce print-server T-300 pack (plus synthetic round-trip for the write path).
Pilot / Cedar	Yes	No (read-only in GUI)	—	—	Xerox D-machine Pilot/Cedar nucleus filesystem (Dolphin/Dorado/Dandelion), structurally unrelated to BFS: physical/logical volume roots (seals 121212₈ / 131313₈), a subvolume table, the VAM free bitmap, and extent-based files behind out-of-band sector labels. Both file-ID generations (32-bit Cedar nucleus / 80-bit original Pilot) and both label schemes (Cedar-nucleus + classic Pilot 12.3). Browse + extract files in the GUI (enumerated by page-label scan across all subvolumes; the nucleus has no name directory, so real names come from the Cedar client name directory — the FS name->FileID B-tree in rootFile[client], decoded when present — then from each file's leader page (XDE volumes name ~90% of files this way, ViewPoint names its boot/system files), and otherwise are synthesized from the file ID); blank-volume creation + add/delete files + installing a client name directory (pilot_probe set-dir) via pilot_probe. Validated against real ViewPoint 2.0 / XDE 5.0 volumes from the Dwarf 6085 emulator (.zdisk) as well as round-trip. (ViewPoint client files have no on-disk name — no leader name and no Pilot central directory; their names live in the desktop / NS-Filing layer, not on the local disk — so they surface by ID.) See the PARC specs under docs/.
Carve (raw recovery)	Yes (read-only)	No	—	—	Fallback for disks with no mountable filesystem: custom bootblock Amiga disks (demos / intros / diagnostics that boot from the boot block and write raw sectors — AmigaDOS labels these "NDOS"), and any superfloppy whose filesystem isn't recognized. Surfaces whole-disk.img, bootblock.bin (Amiga), and carved-blkNNNNNN.{jsonl,json,txt} for each recoverable run of contiguous text. Browse + extract only (rb-cli ls / get). Scans the first 10 MB by default; the browse-view Full scan toggle (CLI --carve-full) scans the whole image.

Partition tables

Scheme	Parse	Edit (resize / add / delete / retype)	Notes
MBR	Yes	Yes	PC standard. Logical partitions inside an extended container are surfaced read-only.
GPT	Yes	Yes	Primary + backup header rewritten with refreshed CRCs on every edit.
APM	Yes	Yes	Apple Partition Map (68k / PowerPC Macs).
RDB	Yes	Bootable flag only	Amiga RDSK. Full RDB editing deferred until the DosEnv geometry story is settled.
SGI	Yes	Yes	SGI Volume Header (IRIX). 16 fixed slots; checksum recomputed on every write; geometry (vh_dp) preserved across edits. rb-cli new-sgi-hdd synthesizes a dvh + EFS-root hard disk from scratch (IRIX 5.3-6.5).
None (superfloppy)	Yes — auto-detects the filesystem at sector 0 (FAT / HFS / HFS+ / Apple DOS 3.3 / CBM DOS / Atari DOS / RS-DOS / OS-9 RBF / DragonDOS / Acorn DFS / ADFS / QDOS / Human68k / Alto BFS / Pilot/Cedar / …)	—	Standard floppy / disk sizes are recognised even without a partition table. Xerox Alto packs (.pdi / .bfs / CopyDisk / Salto .dsk), Pilot/Cedar PDIs (fsFamily=2), and Dwarf 6085 .zdisk images are detected by magic and presented as a single Alto BFS or Pilot/Cedar volume.

The Clonezilla image format is also parsed as a source (MBR, GPT, partclone images, partition table sidecars) for restore — see docs/clonezilla.md.

What works well vs. what to watch out for

• FAT12 / FAT16 / FAT32 → VHD is the best-exercised path. Whole-disk and per-partition export, shrink, grow, and in-place FAT table patching are all covered by tests.
• exFAT / NTFS / HFS / HFS+ / ext / btrfs → VHD will write a correctly sized VHD with the filesystem patched in place, but less of this path is test-covered; verify the exported image by mounting it before trusting a restore from it. Some docs in docs/ predate full coverage — the code now wires resize for every filesystem in the table.
• HFS classic block-size expansion ("Expand HFS Volume…") clones a source volume into a freshly formatted target with a larger allocation block size and a verified-bootable APM layout (DDR + APM map + driver partitions + alt MDB). Useful when an old 2 GB classic-HFS volume runs out of 16-bit block addresses.
• SGI EFS / XFS: EFS is fully read/write/resize. XFS gained a full edit + repair surface (R1-R8 repair pipeline; oracle-validated against xfs_repair) on the v4 format. Open XFS holes (multi-block leaf/node directories, bmap-btree forks, v5/CRC write side) and the planned shrink-via-clone path are tracked in docs/OPEN-WORK.md §2.1 and §2.2. XFS grow is still done at the disk-layout level ("Add free space" + in-OS xfs_growfs).
• ProDOS → VHD is not implemented yet; restore to raw / CHD / Zstd / physical disk works.
• Raw → raw restore always works regardless of filesystem; only the shrink/expand paths depend on filesystem-specific code.
• Write-back to source formats: WOZ2 export is supported (the writer regenerates a clean WOZ from the decoded sector buffer). 2MG, DC42, and DMG are still read-only as sources — to round-trip those, restore to raw / VHD / CHD / Zstd or a physical disk.
• CHD as both source and edit target: rusty-backup uses MAME's native CHD core, so .chd files are first-class — no external chdman required for read, write, browse, or in-place expand (Phase 6c of the disk-expansion workflow re-encodes the CHD with a new logical size).
• Browsing compressed backups: native .zst backups stream-decompress lazily on open, so browsing a multi-gigabyte zstd backup is fast. .chd backups currently require building a full seekable cache on open, which can be slow for large partitions — plan to work around this in a future release.

MiSTer FPGA cores

Rusty Backup can build, browse, and convert images that drop straight into MiSTer FPGA computer cores. The list below is the subset where the full filesystem + container + partition pipeline works end to end. Full per-core status (including outstanding cores) lives in docs/full_MiSTer_support_status.md.

MiSTer core	Filesystem(s)	Media path
ao486 (486 PC)	FAT12 / FAT16 / FAT32 (MBR), ISO9660	Floppy, HDD, CD
PCXT	FAT12 / FAT16 (MBR)	Floppy, HDD
MSX / MSX1 / TurboR	FAT12 / FAT16 (Nextor VHD)	Floppy, HDD
ZXNext (ZX Spectrum Next)	FAT32 / FAT16 / FAT12	SD / HDD (VHD)
TSConf (ZX-Evolution)	FAT32 (non-MBR)	SD / HDD (VHD)
Minimig-AGA (Amiga)	AFFS (OFS/FFS), PFS3, SFS on RDB, ISO9660	Floppy (.adf/.adz), HDD (.hdf/.hdz), CD
MacPlus	HFS	HDD (.hda / .hfv) — 400K MFS floppy outstanding
AtariST	GEMDOS (FAT12 / FAT16), MSA containers	Floppy (.st / .msa); HDD pending AHDI write-side
Apple-II	ProDOS + Apple DOS 3.3	.dsk / .do / .po / .2mg / .woz (sector-order auto-detect)
Atari800	Atari DOS 2 (2.0S / 2.5, read + write)	Floppy .atr / .xfd (single + enhanced density)
ZX-Spectrum	esxDOS FAT	DivMMC / esxDOS SD; native TR-DOS / +3DOS pending
X68000 (Sharp)	Human68k (FAT-derived)	Floppy (.d88 / .xdf / .hdm / .dim — any-to-any conversion + in-place add/delete/mkdir), SASI/SCSI HDD (.hda / .hdf / .hds — read/browse/extract + add/delete/mkdir + in-place grow/shrink + defragmenting repack, incl. real BlueSCSI X68SCSI1 1024-byte-sector images). rb-cli new-x68k-hdd builds self-bootable HDDs from scratch (--system-disk donor.dim clones a Human68k system floppy into the partition; one SWITCH.X /HD on first FDD0 boot installs the partition boot sector and the HDD self-boots to C: thereafter). For users with the well-known hd0.hds donor (100 MB Sharp/Keisoku Giken SCSI HDD image, 104,857,600 bytes), --boot-sector-donor hd0.hds --size 100M --variant scsi overlays the donor's Sharp partition boot sector at build time — zero manual steps, self-boots to C:> on first power-on. MAME-verified on x68000 SASI + x68030 SCSI.
Archie (Acorn Archimedes)	ADFS / FileCore (read)	.adf floppy, bare + Arculator-wrapped .hdf HDD
QL (Sinclair)	QDOS (QXL.WIN, read + write)	HDD (.win)
Amstrad CPC	AMSDOS + CP/M 2.2 / Plus (amstrad_data + amstrad_sys DPBs)	Floppy .dsk
AmstradPCW	CP/M Plus (amstrad_pcw DPB)	Floppy .dsk
TatungEinstein	Xtal-DOS / CP/M (einstein DPB)	Floppy .dsk
Altair8800	CP/M (altair_8in 8-inch floppy + altair_cf CF/HDD DPBs)	Floppy + IDE/CF
MultiComp	CP/M (multicomp DPB)	Floppy .dsk
C64 / C128	CBM DOS (1541 / 1571 / 1581, read + write)	Floppy .d64 / .d71 / .d81
VIC20 / C16 / Plus-4	CBM DOS (1541, read + write)	Floppy .d64
PET / CBM-II	CBM DOS (1541 + 8050/8250 IEEE-488, read + write)	Floppy .d64 / .d80 / .d82
CoCo2 / CoCo3 (Tandy)	RS-DOS / Disk BASIC + OS-9 / NitrOS-9 RBF (both read + write)	Floppy .dsk / .jvc / .vdk (35- / 40-track)
Dragon (Dragon 32/64)	DragonDOS + OS-9 / NitrOS-9 RBF (both read + write)	Floppy .dsk (single- / double-sided 40-track)
BBCMicro / AcornElectron	Acorn DFS (read + write)	Floppy .ssd (single-sided 40- / 80-track)

For X68000 specifically, the floppy converter lets you take an image in any of the four formats Sharp tooling and MiSTer cores expect — XDF (headerless raw), HDM (PC-98 raw), DIM (DiskExplorer DIFC), or D88 (sparse track-table) — and produce any of the others, single-file or in bulk. Geometry inference covers the X68000 + PC-98 set: 1.2 MB 2HD, 1.44 MB 2HD, 720 KB 2DD, and 640 KB 2DD.

Physical drive compatibility

Rusty Backup talks to whatever the OS exposes as a raw block device. Anything that shows up via the platform enumerator (Disk Management / diskutil / /sys/block) is a candidate.

Media	Backup from physical	Restore to physical	Notes
CompactFlash (via USB/PCMCIA reader)	Yes	Yes	Primary use case
SD / microSD / MMC	Yes	Yes
USB flash drives	Yes	Yes
USB-attached IDE / SATA (HDD, SSD)	Yes	Yes	Docks, toasters, bridges
Internal SATA / NVMe drives	Yes	Yes	Requires elevation; verify target
USB floppy drives (1.44 MB, 720 KB)	Yes (as block device)	Yes	Treated as a regular block device; no copy-protection support
5.25" / 3.5" floppies via Kryoflux / Greaseweazle / Applesauce	No (use their tools)	No	Dump to .woz / .dc42 / .2mg and feed that image in
Optical media (CD/DVD/BD)	Yes*	No	Needs additional testing, many/most filesystems support for CD and DVD, I don't think it supports any form of copy protection
Tape drives	No	No

Physical floppies are supported only through the OS block-device layer, which covers standard MFM formats (PC 1.44 MB, 720 KB). Copy-protected, variable speed, or GCR-encoded Apple floppies must be dumped with a flux-level tool first and then ingested as a .woz / .dc42 / .2mg image.

Further reading

• PROJECT-SPEC.md — full design document.
• CONTRIBUTING.md — contributor guide.
• docs/ — per-feature deep dives (VHD export, alignment, code signing, Apple II floppy formats, …).
• docs/linux_486_appliance.md / docs/appliance_hardware_support.md — the bootable Linux backup appliance and its vintage-hardware driver support (which cards work, and how to add more in Buildroot).

Donations

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License

AGPL-3.0 — see LICENSE.