BitSkim0.1

BITSKIM / LOCAL FILE SHARING

Your files.
Any decade.

A new connection for the computers you keep. Send files and folders directly between modern desktops and classic machines.

Get BitSkim 0.1 Explore the apps ↓

One local network. No account. No cloud.

Redrawn Amiga 500 with 1084S monitor and mouseAMIGA
Redrawn IBM PC XT with monitor and keyboardIBM PC
Redrawn Acorn Risc PC with monitor, keyboard and mouseACORN RISC PC
Redrawn Atari Falcon computer with monitor and integrated keyboardATARI
BUILT TO CONNECT

macOS / Windows / AmigaOS / Experimental retro ports

Find your machine ↗

A SMALL APP. A LONG REACH.

Less moving disks.
More moving files.

Keep your favourite computer in the conversation. BitSkim handles the handoff across your local network.

01 — FIND

Open on both computers.

BitSkim discovers nearby computers automatically using broadcasts on your local network. You can also connect by IPv4 address.

02 — SEND

Pick what travels.

Choose files or folders. On Mac, drop them straight onto the other computer.

03 — RECEIVE

Give it a home.

Accept the offer and choose a destination. Follow the progress or cancel when needed.

Modern clients prefer TLS encryption. Retro connections use plaintext. Built for a trusted local network. Read the details ↗

FOUR DECADES. FAMILIAR CONTROLS.

At home on
your desktop.

Actual BitSkim 0.1 windows. Native interfaces with a shared transfer engine underneath.

Mac BitSkim main window showing a local demo receiver
macOS · Nearby computersDrop files or folders onto a computer to start a transfer.
AmigaOS file sharing window with a nearby Mac
AmigaOS · Nearby computersChoose a nearby computer or enter an IPv4 address.
Atari TOS BitSkim main window with file and directory controls
Atari TOS · Nearby computersA compact GEM interface for files, directories and manual connections.
DOS text interface with nearby test computers
DOS · Nearby computersKeyboard navigation, visible transfer status and queue controls.
More application views Settings and file browsers
AmigaOS appearance preferences and theme preview
AmigaOS · AppearanceChoose a shared theme and preview it before saving.
AmigaOS network preferences with visibility and transfer limits
AmigaOS · Network controlsControl visibility, incoming transfers and send/receive limits.
AmigaOS About page with project links and ARexx information
AmigaOS · About BitSkimProject links, release information and ARexx integration.
DOS file browser with tagged-send controls
DOS · File browserBrowse local folders and tag multiple files for sending.

MAKE THE CONNECTION

Find your
machine.

BitSkim is free to download. Both computers need BitSkim and a reachable IPv4 connection. Choose a client below.

Downloads are selected from published GitHub releases; each client shows its available version.

Available clients

Experimental clients

DOS / mTCP

Experimental
Version 0.1

8086 · packet driver required · GPLv3+ with source · hardware coverage pending

Client ZIP ↓ SHA-256
Planned clients · not released

Windows 3.1

Planned
Not released

No client download yet.

Linux

Planned
Not released

No client download yet.

Experimental builds have limited validation; compiling a client does not establish hardware compatibility. Platform details ↗

Browse the source ↗Source archiveBuild from sourceAll releases ↗Release notes

MAKE IT YOUR OWN

Build from source.

Compile a client directly with the supplied platform scripts. Use Python 3.9+, a POSIX shell and the target toolchain; run commands from the project folder.

Requirements and manual build commands

Get the source

Extract the source archive, or clone the repository:

git clone https://github.com/retrocs-org/bitskim.git
cd bitskim

Modern Mac and Windows builds also need Perl, make, curl and initial download access for pinned OpenSSL. Install toolchains separately and export their paths in your shell; standalone commands do not load your external release settings. Generated icons and themes are included.

macOS · Apple silicon

Xcode command-line tools/macOS SDK, Clang and Swift. Targets macOS 13+.

./scripts/build-macos.sh

Output: build/macos/BitSkim.app.

Windows · x64

MinGW-w64 GCC, windres and binutils in PATH; run from a POSIX shell. The first OpenSSL build requires the x86_64-w64-mingw32 tools in PATH, even if compiler variables are set.

./scripts/build-windows.sh

Output: build/windows/BitSkim.exe.

AmigaOS · 68000

AmigaPorts GCC, NDK and libnix with nix20 support.

AMIGA_CC=/path/to/m68k-amigaos-gcc ./scripts/build-amiga.sh

Output: build/amiga/BitSkim.

Experimental clients · manual build commands

Atari · TOS / MiNTNet

Compatible m68k-atari-mint GCC with MiNTLib/GEMlib and STinG headers. Builds all three variants.

ATARI_CC=/path/to/m68k-atari-mint-gcc STING_INCLUDE=/path/to/sting-sdk/include ./scripts/build-atari.sh

Output: build/atari/{sting,mintnet,mintnet060}/BITSKIM.PRG.

RISC OS · ARM2 / StrongARM

Working legacy GCCSDK 2.95.4 AOF/UnixLib, APCS-26. Builds both CPU variants.

RISCOS_CC=/path/to/legacy/gcc ./scripts/build-riscos.sh

Output: build/riscos/{arm2,strongarm}/!BitSkim.

DOS · 8086 / mTCP

Open Watcom 16-bit DOS tools and a configured DOS build runner. The guide also describes the unvalidated Windows-native route.

python3 scripts/build-dos.py --watcom /path/to/open-watcom --runner /path/to/dos-runner

Output: build/dos/BITSKIM.EXE.

Windows Classic · x86

i686 MinGW-w64 GCC and windres in a POSIX shell, with the libmsvcrt-os.a import library. Runtime validation remains pending.

LEGACY_WINDOWS_CC=/path/to/i686-w64-mingw32-gcc LEGACY_WINDOWS_RC=/path/to/i686-w64-mingw32-windres ./scripts/build-windows-legacy.sh

Output: build/windows-legacy/BitSkim.exe.

Check the shared engine

On macOS/Linux, provide a host C compiler named cc and local socket access. Application and hardware testing remain separate.

python3 -m unittest discover -s tests -b

Create a Windows installer

After building the Windows client, provide NSIS 3 and its matching Stubs/Include/Plugins data:

MAKENSIS=/path/to/nsis/bin/makensis NSISDIR=/path/to/nsis/share/nsis ./scripts/build-windows-installer.sh

Finish source, documentation and website edits before compiling: packaging rejects build records after any of those files change. Rebuild affected package targets after edits.

The complete manual build guide ↗ includes target outputs, Atari SDK preparation, Mac disk images and local package creation. It is also included as docs/BUILDING.md in the source archive.

HELP & ANSWERS

Support.

Getting connected, choosing a client, and answers to common questions.

Frequently asked questions
What does the Amiga need?

AmigaOS 3.x, a Workbench screen at least 640×256, and an AmiTCP-compatible TCP/IP stack exposing bsdsocket.library version 4.

What can version 0.1 send?

Files up to 2 GiB minus one byte each, plus nested folders and empty directories on capable clients. Queues, conflict choices, speed limits and session history help manage a transfer. Filesystem metadata is not preserved. See the release notes for feature and platform limits.

Does this work with AirDrop or over the Internet?

BitSkim uses its own protocol; both computers need the app. Version 0.1 is intended for trusted local networks. Keep its listening port off the public Internet.

How do computers find each other?

Open BitSkim on both computers and enable visibility and receiving. BitSkim sends UDP broadcasts on the local network to discover nearby clients automatically. No account or central server is needed.

Why is the other computer missing?

Check that both apps are running, receiving is enabled, and both computers have a reachable IPv4 connection. Guest Wi-Fi, client isolation, routers and VPNs can block broadcasts. Try the other computer’s IPv4 address directly; this still requires a reachable network connection.

Which network ports does BitSkim use?

Discovery uses UDP port 46440. The default TCP listening port is also 46440, although a client can advertise a different listening port. Allow the app through your firewall on your trusted local network. Port forwarding is not needed for local transfers.

Are transfers encrypted?

Mac and modern Windows clients prefer TLS encryption. Retro connections use plaintext. To verify a modern device’s identity, compare verification codes before remembering its public key. Use BitSkim on a trusted local network. Read the security details.

Can a modern computer send files to a classic one?

Yes, when both computers run compatible BitSkim clients and can reach each other over IPv4. Features depend on the receiving client. An experimental build is available to try, but its label does not guarantee compatibility with every machine or network stack.

Will my original filenames and file metadata survive?

BitSkim maps filenames when needed for the destination filesystem. Version 0.1 does not preserve permissions, timestamps, Mac resource forks or retro filetype metadata. Keep an archive of the original files when that information matters.

What does Experimental mean?

These clients have limited runtime or hardware validation. Their download cards and release notes describe the checks completed so far. Planned clients have not been released and are listed separately.

Can I build BitSkim myself?

Yes. One shared source archive contains the project and build instructions. See Build from source for requirements and commands, including a link to the complete platform guide.