AXPbox Alpha emulator

AXPbox is a fork of the discontinued es40 emulator. It could theoretically used for running any operating system that runs on the OpenVMS or Tru64 PALcode (e.g. OpenVMS, Windows 2000, Tru64 UNIX, Linux, NetBSD),).

The emulator supports SCSI, sound, IDE, serial ports, Ethernet (using pcap, or TUN/TAP on Linux) and VGA graphics (using SDL).

Note: active development happens over at the ES40-Emu project. Please go there for the latest improvements and speedups. We try to backport features from ES40-Emu/es40 using LLM's. You should check out that fork if you do not want to use AI code.

OpenVMS 8.4 desktop in AXPbox. Here is a wiki page showing you how to get this CDE desktop running

Windows 2000 build 2128 running on AXPbox. Full guide to install Windows 2000 here

Getting AXPbox

Pre-built binaries for generic Linux amd64, Windows 11 amd64 and macOS amd64 are available for each release, and also as artifacts produced for each commit in CI. T2 SDE has an official package for AXPbox, and openSUSE's Emulators project has an AXPbox package, too. The former gets updated the same day when a release happens, while requests are submitted now the latter that undergo approval of Emulators maintainers.

You can also build from source using CMake, see the next section.

Building from source

You need CMake (3.24+) and a C++17 compiler. Optional dependencies are pcap for networking and SDL3 or X11 for graphics. SDL3 is bundled as a git submodule (third_party/SDL) and is built in statically whenever no system SDL3 is found, so clone with submodules:

git clone --recurse-submodules https://github.com/lenticularis39/axpbox
cd axpbox
# or, for an existing clone:
git submodule update --init

Linux

sudo apt install build-essential cmake libpcap-dev
# GUI (only needed when building the bundled SDL3; skip for headless):
sudo apt install libx11-dev libxext-dev libxrandr-dev libxcursor-dev \
                 libxi-dev libxtst-dev libxfixes-dev libxss-dev libxkbcommon-dev libwayland-dev libegl-dev
# a distro-packaged SDL3 (libsdl3-dev) is used instead when available

cmake -S . -B build -DCMAKE_BUILD_TYPE=Release
cmake --build build -j$(nproc)

The binary is build/axpbox. For a headless build (no GUI) add -DDISABLE_SDL=yes -DDISABLE_X11=yes to the configure step; to build without networking add -DDISABLE_PCAP=yes.

Windows

Requirements:

• Visual Studio 2022 with the "Desktop development with C++" workload (MSVC x64), plus CMake
• the npcap SDK for networking support at build time — unzip it e.g. to C:\pcap
• Npcap installed for networking at run time (any install mode works; wpcap.dll is located at run time, the exe also starts fine without Npcap, just without networking)

SDL3 needs no separate install — the submodule is compiled in statically. From a developer command prompt (or any shell with CMake on the PATH):

git clone --recurse-submodules https://github.com/lenticularis39/axpbox
cd axpbox
cmake -S . -B build -G "Visual Studio 17 2022" -A x64 ^
      -DPCAP_INCLUDE_DIR=C:/pcap/Include ^
      -DPCAP_LIBRARY=C:/pcap/Lib/x64/wpcap.lib
cmake --build build --config Release

The binary is build\Release\axpbox.exe, self-contained (SDL3 is linked statically and pcap is loaded dynamically).

JIT

See the x86-64 JIT section below for the optional asmjit-based JIT lane.

Usage

First invoke the interactive configuration file generator:

axpbox configure

This creates a file named es40.cfg, which you can now modify (the generator UI doesn't allow to set all options). The sample es40.cfg in the repository root documents every available configuration value. After the configuration file and the required ROM image are ready, you can start the emulation:

axpbox run

Please read the Installation Guide for information to get OpenVMS installed in the emulator. A guide for NetBSD is also available on the Wiki

x86-64 JIT

An optional JIT (ported from ES40-Emu/es40, based on asmjit) can be enabled at build time on x86-64 hosts:

git clone https://github.com/lenticularis39/axpbox
cd axpbox # repo folder
git clone https://github.com/asmjit/asmjit third_party/asmjit
git -C third_party/asmjit checkout 0bd5787b54b575ed94bf32ac452153b34385c514
cmake -B build -DCMAKE_BUILD_TYPE=Release -DES40_DISABLE_ASMJIT=OFF
cmake --build build

S3 Trio64 graphics / ARC / Windows NT

The S3 Trio64 emulation (ported from ES40-Emu/es40 uses the real S3 VGA BIOS; obtain 86c764x1.bin from the 86Box ROM set and point the s3 config section at it (see the sample es40.cfg). This is required for the ARC/AlphaBIOS console and Windows NT-family guests: flash AlphaBIOS from the Alpha Systems Firmware v7.3 CD, then enter arc at the SRM prompt.

Serial consoles, networking, and sound

• Serial ports: the sample config attaches both UARTs as null_attach (present but unconnected), so the emulator starts without waiting for anything and the console lives on the VGA window (vga_console = true). To use a telnet console instead, set port = 21264; in a serial section — note the emulator then waits at startup until a client connects (nc localhost 21264). Ports left out of the config entirely are synthesized as null_attach automatically.

• Networking: the DEC 21143 NIC (pci0.4 = dec21143) connects to the host through one of two backends, selected with type in the nic config section:

  • type = "pcap" (default): captures on an existing host interface. Set adapter = "eth0"; (Linux) or the \Device\NPF_{...} name (Windows/Npcap). On Linux, grant the binary capture permission once:

    sudo setcap cap_net_raw,cap_net_admin+eip ./axpbox
    

    otherwise startup fails with "Error opening adapter". On Windows, install Npcap; wpcap.dll is located automatically at run time. Don't leave adapter unset on unattended runs — the emulator interactively asks which adapter to use.
  • type = "tap" (Linux only): uses a TUN/TAP device instead of capturing — the guest becomes reachable from the host (and can be bridged onto the LAN). Options: adapter = "tap0"; (device name, created if needed — requires CAP_NET_ADMIN or root), host_ip = "10.0.0.1/24"; (optional host-side IP for the tap), bridge = "br0"; (optional: create a bridge and add the tap to it), uplink = "eno1"; (optional: also add this physical NIC to the bridge), tap_create = true;.

  Optional values for both backends: mac (default 08-00-2B-E5-40-<nic#>), queue (rx queue depth, default 1024), crc, trace_packets. The sample es40.cfg documents every option.

• Sound: pci1.1 = es1370 {} adds an Ensoniq AudioPCI ES1370 (SDL builds). Guest drivers exist for Windows NT 4; other guests ignore it.

• Mouse: click the window to grab, Ctrl+F10 to release; mouse.speed, mouse.invert_x, mouse.invert_y in the sdl section tune it (see the WSLg note below). video.scale_ratio / video.scale_change_enable control window scaling (Ctrl+PageUp / Ctrl+PageDown at runtime).

• CD images: a cdrom file ending in .cue is parsed as a BIN/CUE image (multi-file, MODE1/MODE2/audio tracks); anything else is treated as a flat ISO.

Headless testing and input-injection hooks

For automated or headless testing (CI, AI, scripted firmware navigation, driving the emulator over SSH), the SDL GUI honors a set of debug environment variables. They are read at startup; unset means disabled. Combined with SDL_VIDEO_DRIVER=offscreen the whole GUI stack runs without any visible window or display server.

Variable	Effect
AXPBOX_DUMP_FB=<prefix>	Write the emulated screen as a PPM image (<prefix>-NNN-WxH.ppm) every ~2 seconds. This is how you "see" the VGA output on a headless run.
AXPBOX_KEYSCRIPT="<sec>:<key>,..."	Press named keys at fixed second offsets from GUI start, e.g. AXPBOX_KEYSCRIPT="40:a,41:r,42:c,43:enter" types arc + Enter at the SRM prompt 40 s in. Good for boot flows whose timing you already know.
AXPBOX_KEYPIPE=<file>	Interactive variant: keys appended to <file> while the emulator runs are typed into the guest (one token per ~120 ms). Example: echo "f2 down down enter" >> keys.txt navigates an AlphaBIOS menu. Start with an empty file; the emulator remembers how far it has read.
AXPBOX_AUTOKEY_ENTER=<sec>	Press Enter every <sec> seconds (blunt tool for firmware "press any key" prompts).
AXPBOX_AUTOMOUSE=<sec>	Starting <sec> seconds in, inject synthetic PS/2 mouse motion (a repeating square pattern plus a periodic left click) directly into the guest, bypassing host input entirely. If the guest cursor moves with this but not with your real mouse, the problem is host-side SDL event delivery, not the emulated hardware.
AXPBOX_MOUSE_DEBUG=1	Trace every host mouse-motion event, grab/focus transition, and relative-mouse-mode failure to stderr (MOUSEDBG ... lines).
AXPBOX_PC_SAMPLE=1	Print the guest program counter on every CPU state poll (~100 ms) — identifies where a guest is stuck on headless runs.

Key names for AXPBOX_KEYSCRIPT/AXPBOX_KEYPIPE: a–z, 0–9, enter, esc, tab, space, up, down, left, right, del, ins, home, end, bksp, bslash, dot, minus, equals, f1–f12, pgup, pgdn.

A typical fully headless firmware run:

SDL_VIDEO_DRIVER=offscreen AXPBOX_DUMP_FB=fb \
AXPBOX_KEYPIPE=keys.txt AXPBOX_KEYSCRIPT="40:a,41:r,42:c,43:enter" \
axpbox run &
# ... watch fb-*.ppm to see the screen, echo keys >> keys.txt to react

Note: a serial section configured with a port waits for a telnet connection at startup before the GUI comes up — connect a client (e.g. nc localhost <port>) or configure null_attach = true for unattended runs.

Mouse on WSLg / Wayland

Click inside the emulator window to grab the mouse; Ctrl+F10 releases it. On WSLg (Windows Subsystem for Linux GUI) the default Wayland backend delivers no relative mouse motion while the grab is active — the guest pointer never moves even though the grab succeeds. Run the emulator through XWayland instead:

SDL_VIDEO_DRIVER=x11 DISPLAY=:0 SDL_RENDER_DRIVER=software axpbox run

(SDL_RENDER_DRIVER=software avoids a fatal GLX error under WSLg's XWayland.) Diagnose mouse problems with AXPBOX_MOUSE_DEBUG=1: motion lines with grab=1 mean host input reaches the guest; none after a grab -> 1 line means the host backend isn't delivering relative motion.

Changes in comparison with the original es40

• Renamed from es40 to AXPbox to avoid confusion with the physical machine (AlphaServer ES40)
• CMake is used for compilation instead of autotools
• OpenVMS host support was dropped
• es40 and es40_cfg were merged into one executable (axpbox)
• The code was cleaned to compile without warnings on most compilers
• Code modernizing, replacing POCO framework parts by native C++11 counterparts not available in 2008 (std::threads, etc)
• Incorporate various patches from other es40 forks, for example, added MC146818 periodic interrupt to allow netbsd to boot and install, skip_memtest for faster booting.
• The ES40-Emu/es40 revival work is ported (at its 2026 state): MAME-based S3 Trio64/IBM 8514A graphics, ARC/AlphaBIOS + Windows NT/2000 device support, wall-clock guest timing, interpreter correctness fixes, firmware flash updates with system reset, and the optional asmjit x86-64 JIT.
• Bug fixes, less segfaults, overall less crashes.
• More documentation and usage information on the various features and operating systems

What doesn't work (also see issues)

• Some guest operating systems (see Guest support)
• Multiple CPU system emulation
• Running on big endian platforms
• Some SCSI and IDE commands
• Copying large files between IDE CD-ROM to IDE hard drive (this usually doesn't affect OpenVMS installation)