Run the legacy DOS terminal program IYAGI 5.3 over modern SSH by wrapping it with DOSBox-Staging and a local Go bridge that emulates modem behavior.

This project targets:

• Local Linux runs (tools/run-dosbox.sh)
• Linux AppImage packaging
• Windows portable package/installer flow
• macOS app bundle/DMG flow

• Runs IYAGI 5.3 inside DOSBox
• Connects IYAGI COM port traffic to a local bridge (modem-like AT command parser)
• Converts ATDT... into SSH connection attempts
• Supports SSH-BBS style login flow (SSH_AUTH_MODE=bbs) or key-based mode (SSH_AUTH_MODE=key)
• Handles Korean encoding conversion between IYAGI and UTF-8 servers
• Plays modem-style dial/busy/ringing/connect sounds

IYAGI (DOS app)
 -> COM4 in DOSBox-Staging
 -> nullmodem tcp 127.0.0.1:<bridge_port>
 -> bridge (Go)
 -> ssh client process
 -> target SSH server / SSH-BBS

IYAGI still behaves like a dial-up terminal from the user perspective:

• AT / ATDT... / ATH / ATO style interactions
• modem-like response strings (OK, CONNECT, NO CARRIER, etc.)

From repository root:

task deps
./tools/run-dosbox.sh

What task deps does:

• extracts software/iyagi53dos.zip (only if not already extracted)
• downloads portable DOSBox-Staging into third_party/dosbox-staging

First run creates/uses:

• iyagi-data/.env
• iyagi-data/app/IYAGI
• iyagi-data/downloads

In IYAGI terminal:

• ATDT<host>:<port> -> dial exact target
• ATDT=<host>:<port> -> same as above (= prefix supported)
• ATDT<host> -> defaults to SSH port 22
• ATDT=<user>@<host>:<port> -> override SSH user from dial string
  • example: ATDT=ssh@localhost:40000 -> runs SSH with {userhost}=ssh@localhost, -p 40000
• ATDT (empty target) -> tone then NO CARRIER
• ATDT; -> tone then OK
• ATDT-<target> -> fast dial (skip dial/ring sounds)

DTMF playback mapping:

• Digits 0-9, *, # play their own tones
• Letters in dial target are converted by phone keypad mapping:
  • ABC->2, DEF->3, GHI->4, JKL->5, MNO->6, PQRS->7, TUV->8, WXYZ->9
  • example: ATDT=bbs.runable.app:40000 plays DTMF using mapped digits for bbsrunableapp

Additional modem command:

• CLS / CLEAR -> prints 28 blank lines in command mode

The bridge parses ATDT target text directly and attempts outbound SSH accordingly.

Main config template:

• resources/common/.env.example

Local runtime config:

• iyagi-data/.env

• SSH_AUTH_MODE:
  • bbs (default): no local key required
  • key: use local keypair in iyagi-data/keys
• BRIDGE_PORT: local bridge listen port (auto supported)
• BRIDGE_CONNECT_TIMEOUT_SEC: outbound probe timeout
• BRIDGE_BUSY_REPEAT, BRIDGE_BUSY_GAP_MS
• BRIDGE_DTMF_GAP_MS
• BRIDGE_POST_DTMF_DELAY_MS
• BRIDGE_CLIENT_ENCODING, BRIDGE_SERVER_ENCODING
• BRIDGE_SERVER_REPAIR_MOJIBAKE
• BRIDGE_DEBUG (0 default in .env.example; set 1 only for troubleshooting). Dev scripts tools/run-dosbox.sh / tools/run-appimage.sh enable debug unless you pass BRIDGE_DEBUG=0 or IYAGI_BRIDGE_DEBUG_OVERRIDE=0 respectively.

DOSBox timing/display:

• DOSBOX_CPU_CORE (default simple)
• DOSBOX_CPU_CPUTYPE (default 386)
• DOSBOX_CPU_CYCLES (numeric for Staging path)
• DOSBOX_FRAMESKIP (0-10, default 1)
• DOSBOX_VIDEO_BACKEND (auto|x11|wayland)
• DOSBOX_WAYLAND_STRICT

Scanline shader toggle (DOSBox-Staging):

• DOSBOX_SCANLINES=0|1
• DOSBOX_GLSHADER (example: crt/vga-1080p)
• DOSBOX_SCANLINE_WINDOWRES (example: 1280x960)

When DOSBOX_SCANLINES=1, Staging switches to OpenGL shader mode.

Recommended shader presets:

• Sharp: crt/vga-1080p-fake-double-scan
• Balanced: crt/vga-1080p
• Soft: crt/composite-1080p

You can list available shaders:

third_party/dosbox-staging/unpacked/dosbox --list-glshaders

Current project defaults are tuned for terminal use:

• Mouse input disabled in DOS guest:
  • mouse_capture=nomouse
  • dos_mouse_driver=false
• DOSBox ethernet/slirp disabled:
  • [ethernet] ne2000=false
• MIDI output disabled:
  • mididevice=none

These reduce irrelevant warnings/noise and avoid input interference in IYAGI.

bash tools/build-linux.sh

Output:

• dist/IYAGI-linux-x86_64.AppImage

./tools/run-appimage.sh

By default this helper sets USER_DATA_ROOT to iyagi-data/ (same .env as run-dosbox.sh). To test the packaged default user directory instead, run RUN_APPIMAGE_XDG=1 ./tools/run-appimage.sh (uses ~/.local/share/iyagi-terminal/, same single-tree layout as iyagi-data/).

Local:

• tools/run-dosbox.sh (portable DOSBox-Staging-focused)

Packaged launchers:

• Linux AppImage: resources/linux/launch.sh
• macOS: resources/macos/launcher
• Windows: resources/windows/launch.bat

Cross-platform parity for launch behavior is intentional and maintained.

Taskfile.yml includes:

• task deps (extract IYAGI + download DOSBox)
• task iyagi:extract
• task dosbox:download
• task keys:generate
• task bridge:embed-sounds
• task bridge:build

resources/common/.env.example is what ships inside packages and becomes a new user’s .env on first copy. It is not auto-filled from iyagi-data/.env at build time (that tree is local and often gitignored).

After you settle on good DOSBOX_* / BRIDGE_* values in iyagi-data/.env, port those lines into .env.example (e.g. diff -u resources/common/.env.example iyagi-data/.env) so AppImage and other installs get the same defaults—without copying secrets or personal IYAGI_USER / port choices unless they are meant for everyone.

Existing installs: the launcher copies .env.example → .env only when .env is missing. Updating the repo or rebuilding the AppImage does not overwrite ~/.local/share/iyagi-terminal/.env. No Python step rewrites it. To refresh defaults, remove or rename that .env (or merge changes by hand). Verify what shipped inside the AppImage: ./dist/IYAGI-linux-x86_64.AppImage --appimage-extract then head squashfs-root/.env.example (or inspect AppDir/.env.example mid-build before appimagetool runs).

• Root: iyagi-data/
• App files: iyagi-data/app/IYAGI
• Downloads: iyagi-data/downloads
• Env: iyagi-data/.env

• User data (.env, keys/, app/, downloads/, staging/): ${XDG_DATA_HOME:-~/.local/share}/iyagi-terminal/ (same layout as iyagi-data/ from run-dosbox.sh)

Override both with:

• USER_DATA_ROOT

• AppImage still behaves differently from ./tools/run-appimage.sh
  • Rebuild after launcher changes: bash tools/build-linux.sh (running dist/*.AppImage uses whatever was baked into that file).
  • run-appimage.sh sets USER_DATA_ROOT to iyagi-data/; double‐clicking the AppImage uses ~/.local/share/iyagi-terminal/ — compare the two .env files if timing differs.
  • A DOSBOX_BIN exported in your desktop session (e.g. from a dev profile) used to override even DOSBOX_SOURCE=bundled; the AppImage launcher now drops inherited DOSBOX_BIN unless you set it on the same command line as the AppImage.
  • On start, the launcher prints DOSBox profile: with cpu_cycles, frameskip, and output — confirm they match what you expect.
  • Run env | grep -E '^DOSBOX_' before launching: values like DOSBOX_CPU_CYCLES=max are ignored by the AppImage launcher unless they are plain integers (otherwise defaults apply).
• Cursor looks too fast:
  • lower DOSBOX_CPU_CYCLES (for example 1200 -> 1000 -> 800)
• Shader enabled but window looks too small:
  • use DOSBOX_SCANLINE_WINDOWRES=1280x960 for 2x-like 640x480 presentation
• Dial sounds too fast:
  • increase BRIDGE_DTMF_GAP_MS
• Need visible post-dial pause:
  • increase BRIDGE_POST_DTMF_DELAY_MS

This project is licensed under PolyForm Noncommercial 1.0.0.
IYAGI is freeware but not open source; verify redistribution rights for your target distribution channel.