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System Configuration

Configure the peripherals attached to the PDP‑11. Structural changes are committed with the "Apply" button, which restarts the machine so the emulated hardware matches the configuration. Others apply immediately.

Storage

Manage storage media: load a paper tape, import disk or tape images by drag & drop, and unmount mounted images.

yaPDP — Yet Another PDP‑11/70 Emulator

About This Project

This is a PDP‑11/70 emulator that just works out of the box — no plugins, no downloads, no configuration. Just run it and you're standing in front of a DEC minicomputer.

What makes it special

Quick Start

In a hurry? Use the magic wand button pinned to the top-right corner of the Panel page — it does it all in one click: picks a guest OS, reconfigures the machine, reboots it, and types the boot (and login) for you. The manual walk-through below follows the same route.

1. Open the PDP‑11/70 emulator.
2. At the Boot> prompt, type boot rp1 and press ENTER.
3. BSD 2.11 will autoboot into multiuser mode. Login as root (no password).
4. Try ls, ps -aux, df — or compile a C program with cc.

Switching pages

Use the sidebar to switch between:

• Panel — the front panel with switches and LEDs
• Teletype — the Model 33 ASR teletype console
• VT52 — the DECscope VT52 video terminal
• Display — the VT11 vector-graphics CRT terminal (shown only when configured)
• Info — detailed instructions and OS reference

A simple light chaser

Toggle this into the front panel to see the address and data LEDs dance:

Address  Data    Code        Switch commands
                            HALT, 001000, LOAD ADDRESS
001000   012700  mov #1,r0   012700, DEPOSIT
001002   000001              000001, DEPOSIT
001004   006100  rol r0      006100, DEPOSIT
001006   000005  reset       000005, DEPOSIT
001010   000775  br .-4      000775, DEPOSIT
                            001000, LOAD ADDRESS, ENABLE, START

Restart the bootloader

HALT, 120000, LOAD ADDRESS, ENABLE, START

Guest Operating Systems

The emulator ships with ready-to-boot disk and tape images. Just type boot at the Boot> prompt.

Example boot of Unix V5

Boot> boot rk0
@unix

login: root
# who
root    tty8 Mar 21 12:09
# cat /etc/passwd
root::0:1::/:
daemon::1:1::/bin:
bin::3:1::/bin:
# cat > hello.c
main()
{
    printf("Hello world\n");
}
^D
# cc hello.c
# a.out
Hello world
#

Acknowledgments

This project stands on the shoulders of giants.

Paul Nankervis — Original PDP‑11 Emulator

Paul wrote the original pdp11-js emulator, which this repository is forked from. His meticulous work — cycle‑accurate CPU emulation, beautifully rendered front panels, and a meticulously curated collection of vintage operating systems — made this project possible.

"I met my core objective — I can now see the RSTS/E console light pattern that I was looking for."
— Paul Nankervis

Norbert Landsteiner (mass:werk) — Google60 Teletype

The Model 33 ASR teletype emulation is adapted from Google60 by Norbert Landsteiner of mass:werk. Google60 is a brilliant simulation of the Google search interface as it would have appeared on a Model 33 ASR Teletype in the 1960s/1970s. Norbert's meticulous implementation — from the 3D keycaps to the paper advance animation and authentic sound effects — brings the teletype to life.

Additional Sources

• Bitsavers — DEC PDP‑11 documentation archive
• Bitsavers Software — PDP‑11 software and disk images
• The Unix Heritage Society (TUHS) — Preserving UNIX history
• RSTS.ORG — RSTS/E community and software preservation

Links

Happy emulating!

— Alexei Eskenazi amesk<alexei.eskenazi@gmail.com>
— Created and maintained with love for the DEC era