OPEN SOURCE · 2026 · MIT LICENSE

68kBBS/

A period-authentic bulletin board system for 68k Macintosh computers running System 6/7, written in Clarus and serving callers over the Mac's modem serial port.

lang
Clarus
targets
68k Mac · System 6/7
terminals
ASCII · ANSI · VT100 · PETSCII
transfers
XMODEM · YMODEM · ZMODEM
storage
vDB databases
license
MIT
view on GitHub

## why

68kBBS is a bulletin board system that runs on a real 68k Macintosh and answers calls on its modem port, the way a BBS would have in the late '80s. Callers can use a wide range of retro terminals: ASCII, ANSI, VT100, and PETSCII, at 40 or 80 columns. It also works with modern telnet clients through a modem emulator.

It is also the first real-world application written in Clarus, my language for native System 6/7 apps. Building it helped iron out problems in the language and improve its usability.

fig. 1 — the 68kBBS sysop window on a Macintosh SE: line status, recent callers, and the modem log
The 68kBBS window on a black-and-white Mac: a line panel showing a connected VT100 caller named Vaelen on the Boards screen, a table of recent callers, and a timestamped log of modem commands, a telnet client being detected, and the user logging in

## features

  • Message boards and private mail. Paged post lists, a framed post reader, and a line editor with the classic /S /A /L /D /E /I /R commands.
  • File areas and transfers. XMODEM, XMODEM-1K, YMODEM, and ZMODEM downloads and uploads. Uploads wait for sysop approval.
  • FidoNet. Echomail and netmail as a leaf node on an FTN network, using EMSI sessions and ZMODEM.
  • Games. A GW-BASIC-flavored BASIC interpreter written in Clarus runs .BAS door games. Super Star Trek ships as the sample.
  • Terminal-aware rendering. Box-drawn tables and paged views in ASCII, ANSI (cp437), VT100 (DEC Special Graphics), and PETSCII (Commodore).
  • Sysop tools. User, board, and file-area editors, a login log, banned usernames, a message of the day, and a graffiti wall.

Data lives in vDB-format databases, using a journaled B-tree engine written in Clarus.

## running it

The build produces a MacBinary application for the Mac. For development, a Snow emulated Mac II has its modem port bridged to TCP, and a bundled modem emulator plays the part of a Hayes modem so you can call the BBS with telnet.

← cd ../projects