RetroSlack

Classic Macintosh Plus Slack client. The Mac speaks HTTP-over-serial (RHTTP); networking, TLS, and Slack live on the macOS host (desktop NSE). Guest Mac binaries are identical in Snow and on hardware (stock Serial Manager only). Slack tokens never leave the host.

Environment	Path to the Plus	Slack
Development	Snow modem TCP bridge (tcp://127.0.0.1:1984)	desktop NSE (libcurl + http://rs/ cache)
Hardware	macOS USB-serial → Arduino (byte copy) → RS-422 → Plus Mini-DIN-8 modem port	same desktop NSE on that USB serial device

macOS  NSE / hellomacintosh
  USB serial @ 19200 8N1
    Arduino (passthrough)
      RS-422 conversion
        Macintosh Plus modem port (Mini-DIN-8)

The Arduino is not on Ethernet. It is a USB–UART bridge; the MacBook talks Slack, the Plus talks RHTTP over RS-422. The Mac only requests the compact rows it intends to render.

Demo: Slack on a 1986 Macintosh Plus (LinkedIn). Serial deploy uses HelloMacintosh.

HelloMacintosh (required for serial deploy)

This repository is the Slack client. Pushing a rebuilt app over the modem port is a separate project:

HelloMacintosh — resident loader on the Plus + hellomacintosh host CLI + Arduino USB–serial bridge.

Clone it yourself (sibling directory or into HelloMacintosh/ here) or let bootstrap do it. It is not vendored and is not a git submodule; override the checkout with HELLOMACINTOSH_DIR or the clone URL with HELLOMACINTOSH_REPO.

# optional, if you prefer a sibling clone:
git clone https://github.com/kApp-Oliver/HelloMacintosh.git ../HelloMacintosh
export HELLOMACINTOSH_DIR="$PWD/../HelloMacintosh"

Quick start

1. Place a legally obtained Macintosh Plus ROM at ROMS/Mac-Plus.ROM (gitignored; not needed for a real Plus).
2. Copy .env.example → .env and set SLACK_USER_TOKEN or SLACK_BOT_TOKEN. Never commit .env.
3. Bootstrap toolchain, clone HelloMacintosh, and build the desktop NSE + CLI:

make bootstrap   # Homebrew, Retro68, Snow, HelloMacintosh clone, host tools
make mac

Emulator (Snow)

Prepare a System disk (see docs/SETUP.md), then:

make run         # NSE + Snow (modem TCP bridge on 127.0.0.1:1984)

With HelloMacintosh frontmost on the emulated Plus, deploy the client in another terminal:

make deploy SNOW=1
# or: ./scripts/hellomacintosh --serial tcp://127.0.0.1:1984 run build/mac/RetroSlack.bin

Real Plus over serial

Install and leave HelloMacintosh running on the Plus (see that repo’s README). Flash the Arduino passthrough there (./scripts/flash-bridge.sh). Then from RetroSlack:

make deploy SERIAL=/dev/cu.usbserial-XXXX
./build/host/nse --serial /dev/cu.usbserial-XXXX --baud 19200 --verbose

Stop NSE before the next hellomacintosh stop / run — only one host process can own the USB serial device.

./scripts/hellomacintosh is a wrapper around the cloned HelloMacintosh CLI (HM_SERIAL or --serial).

Layout

• protocol/ — portable RHTTP framing (host + Mac)
• host/nse/ — desktop Network Serial Emulator (Slack + http://rs/ over serial)
• arduino/nse/ — experimental on-device Ethernet sketch (not the supported link)
• mac/ — Retro68 guests (RetroSlack, RHTTPTest)
• scripts/ — bootstrap, build, run, serial deploy
• docs/ — setup, protocol, hardware, debugging, display API

The USB–serial Arduino firmware is in HelloMacintosh (arduino/bridge). HelloMacintosh/ is a local clone only (gitignored). Hello World drafts under tutorials/ are local for now (also gitignored).

Docs

• docs/SETUP.md — Snow, Retro68, ROM, System, HelloMacintosh
• docs/HARNESS.md — deploying RetroSlack with HelloMacintosh
• docs/PROTOCOL.md — RHTTP wire format
• docs/DISPLAY_API.md — host Slack cache + tiny http://rs/ payloads
• docs/REAL_HARDWARE.md — real Plus + Arduino
• docs/DEBUGGING.md — Cursor / LLDB / serial logs
• SECURITY.md — tokens, ROMs, what not to commit

Legal

Apple ROM and System software are not redistributed. You must supply your own legally obtained copies. Macintosh is a trademark of Apple Inc. Slack tokens stay on the macOS NSE — never on the Mac or in git.