It is capable of running UNIX 5 upto and including UNIX 7 in multi-user mode. Since recently (April 12, 2026) it can also run BSD 2.11 UNIX in multi-user mode on e.g. an ESP32 (using DZ11 serial port multiplexer emulation). Floating point emulation is missing but that'll change eventually.

Devices supported:

• RK05 (disk)
• RL02 (disk)
• RP06/RP07 (disk)
• KW11-L (line time clock)
• DC11 (serial line interface - emulated via tcp sockets (port 1101 and further) and tty-devices on posix; on ESP32/PICO a real serial port is used)
• DZ11 (serial line multiplexer, see DC11 for details)
• TM11 (tape)

GitHub link: kek on GitHub

Thanks a lot to Neil Webber for his help and for his python PDP emulator (which allowed me to compare disassembly of runs). Neil's emulator can be found on github.

An ESP32-S3 takes about 5 minutes to boot BSD 2.11, a Teensy 4.1 around 1 minute and an Intel i5-11400H needs a second or 2.

For benchmarks, look here.

Most things can be configured via the commandline. Run "kek -h" to see a list of commandline switches.

In the console (run kek with -d), there's on-line help available by entering "help" (+ enter). "0gt;" is the debugger-prompt.

Kek can create snapshots. That way you can restart the emulated system exactly from the point you snapshotted it. Enter "ser filename" in the console/debugger for that. Afterwards kek can be (re-)started with "kek -D filename". Note: kek must be started with the -P switch for this to work (=create disk snapshots).

It can also use a PiDP11 for the blinkenlights. For that, only run server11 on the PiDP11 and start kek with -8 ip-address-of-the-pidp11.

• configure the host-network: cfgnet / startnet

  0>startnet
  Start Ethernet
  Wait for DHCP
  
  Local IP address: 192.168.65.34
  * Adding DZ11
  

• then configure the deqna emulation (deqna + backend where backend is e.g. vxlan, teensy4.1, see help)

  0>deqna teensy4.1
  MAC address: 08:00:2b:2d:cf:46
  DEQNA emulation initialized
  

• after that, configure a disk using cfgdisk - do not forget to load the bootloader (in the cfgdisk menu)

  0>cfgdisk
  1. RK05, 2. RL02, 3. RP06, 9. abort > 2
  Select cartridge to setup, 1. to add a cartridge, 2. to load a bootloader or 9. to exit > 2
  Bootloader loaded
  Select cartridge to setup, 1. to add a cartridge, 2. to load a bootloader or 9. to exit > 1
  1. local disk, 2. network disk (NBD), 9. abort > 1
  Enter filename ("dir" for listing or empty to abort): >xxdp_rl02.dsk
  Opening file: xxdp_rl02.dsk
  Cartridge loaded
   A. xxdp_rl02.dsk
  Select cartridge to setup, 1. to add a cartridge, 2. to load a bootloader or 9. to exit > 9
  

• when all of that is finished, enter: go

  0>go
  
  
  CHMDLD0 XXDP+ DL MONITOR
  BOOTED VIA UNIT 0
  28K UNIBUS SYSTEM
  
  ENTER DATE (DD-MMM-YY):
  

Here I run Kek on a Teensy 4.1 microcontroller:

Test setup: Wemos32 with a card-reader and a serial port and a led ring (which simulates the panel):

Running on an ESP32 connected to a real VT510 terminal.
Lolin S2 mini ESP32 running UNIX 7 with the included chess program:

A Teensy 4.1 running Kek. The LED panel is the simulated front-panel.

In this photo it (old version of kek) runs the XXDP diagnostics software. It booted over the network using the NBD protocol (this is a convenience feature of the emulator).

Picture on an ESP32S3 on which BSD 2.11 is running. Only the ESP though :-) This ESP32S3 has 4.3 MB of RAM (and 8 MB flash): more than enough to run a multi-user BSD setup.

Also a 'SHA2017 badge' is capable of running this emulator:

Running on Linux (also runs on *BSD, macos and microsoft windows systems):

Running on Linux with the "imgui" GUI:

Old video showing it running UNIX 5 (in debug mode):

More recent video showing it booting UNIX 7:

Another more recent video showing it booting UNIX 7 and playing chess:

Multi user on an ESP32:

May 25, 2026 my Kek instance is now reachable via telnet on pdp.komputilo.nl, username guest.

May 16, 2026 Teensy 4.1 support

May 13, 2026 brings a port to the RP2040 (Raspberry Pi Pico RP2040 microprocessor).

Since May 11, 2026 it is somewhat capable of emulating an Ethernet adapter (DEQNA). I implemented a very limited and simple HTTP-server for it. Things are reachable on http://pdp.komputilo.nl:8080/ (no ip6, no https) until it crashes.