What Can You Run On A 1960s Univac? Anything You’re Willing To Wait For!

Nathan Farlow ran a Minecraft server (partially) on a surviving operational UNIVAC 1219B from the 1960s. The UNIVAC's unusual 18-bit architecture with one's complement arithmetic made modern software support nearly impossible, so the approach was to write a RISC-V emulator in UNIVAC assembly, then compile modern code to RISC-V. A Rust-based UNIVAC emulator was built first for testing. Claude Code proved unable to handle UNIVAC assembly, so the emulator was written by hand. Results included rendering a single NES frame in 40 minutes and establishing a TCP/IP handshake between the 1960s machine and a modern laptop for a partial Minecraft login.