March 28, 2026
1976 boots, internet loses it
Circuit-level PDP-11/34 emulator
A 1976 computer reborn in your browser, and commenters go cosmic
TLDR: A painstaking emulator revives the 1976 PDP‑11/34 with circuit‑accurate detail, complete with a photo‑real front panel you can try in your browser. Commenters bounced between cosmic jokes and pure excitement, with a side debate over whether this obsessive realism is nerd nirvana or overkill.
The internet’s retro fans are having a moment. A new project called ll/34 recreates a 1976 PDP‑11/34 minicomputer so precisely it mimics the original’s timing—and even its quirks. The twist? There’s a photo‑real front panel you can click, and a WebAssembly demo that lets you run it right in your browser. One commenter deadpanned, “This was probably how our universe got started,” setting the tone: equal parts awe and cosmic-level nerd joy.
The strongest vibes? Astonishment that someone rebuilt a 1970s machine at the circuit level—down to the micro-instructions and clock cycles—so it behaves like the real hardware. The hottest call-to-action came from a user dropping the “Run a PDP‑11/34 in your browser” link, which sent readers stampeding to mash virtual switches like it’s disco night. Meanwhile, the light drama: a familiar split between “accuracy purists” who love that this can reproduce real hardware bugs, and “just-run-the-thing” folks who wonder if this is glorious overkill when simpler emulators exist.
Humor stayed strong: cosmos jokes, time‑machine quips, and “my desk fan just turned into a VT100 terminal” energy. Bottom line: it’s not just a retro emulator—it’s a museum exhibit you can play with, and the crowd is loving the spectacle.
Key Points
- •ll/34 emulates the PDP-11/34A at circuit level using reverse-engineered ROM truth tables, microcode, and precise clock modeling.
- •The emulator supports a timing-accurate UNIBUS backplane and devices including KD11-EA CPU, M9301 boot card, DL11, KW11, RK05, RL01/02, tape reader, and a VT100 terminal.
- •A C-based datapath models 74xx gates and a 4-slice 16-bit 74S181 ALU, with microcode stored as 512x48-bit bipolar PROMs and reconstructed combinational ROMs.
- •Subsystems include an MMU with PAR/PDR management, a delay-line clock generator with bus wait handling, real-time pacing, and an interrupt arbiter approximating UNIBUS priorities.
- •Operational tools include a Programmer Console, Debug Console, and a built-in logic analyzer, plus a photorealistic WebAssembly front panel GUI.