A work-in-progress PlayStation 1 emulator written entirely in Ruby. Implements the MIPS R3000A CPU, GTE, GPU (software rasteriser), DMA, interrupts, timers, CD-ROM stub, SIO0 controller, and a minimal SPU — enough to boot the SCPH1001 BIOS into the Memory Card / CD-ROM shell. Ships an SDL2-backed front-end via the `psx` command. A BIOS image is not included and must be supplied by the user.