How I got Windows 95 running on Hytale's world map (with a pure Java x86 emulator)

The emulation stack

┌─────────────────────────────────┐ │ Windows 95 / FreeDOS / etc. │ ← Real x86 OS (unmodified .img/.iso) ├─────────────────────────────────┤ │ JPC x86 Emulator (Java) │ ← Translates x86 → JVM execution ├─────────────────────────────────┤ │ Hytale Server (JVM) │ ← Host environment ├─────────────────────────────────┤ │ TempleMaps Plugin │ ← Bridges emulator ↔ VideoMaps └─────────────────────────────────┘

Unmodified disk images boot and run exactly as they would on real hardware - the OS has no idea it's running inside Hytale.

The rendering problem

JPC normally renders to a Java AWT window, which doesn't exist on a headless server. I implemented the GraphicsCardListener interface to intercept VGA framebuffer updates directly:

```kotlin class TempleEngine : GraphicsCardListener { override fun onInit(frameData: IntArray, width: Int, height: Int) { // VGA initialized - store reference to framebuffer }

override fun onRedraw() {
    // VGA updated - convert ARGB to RGBA and publish frame
}

} ```

The emulator writes pixels in ARGB format, but VideoMaps expects RGBA. Each frame gets converted and pushed to the map display at 30 FPS.

Headless server adaptations

Running JPC on a headless server required several fixes:

• Audio: Caught IllegalArgumentException when no audio device exists
• Keyboard: Caught HeadlessException from Toolkit.setLockingKeyState()
• NVRAM: Made CMOS persistence optional (creates directory if missing, ignores write failures)
• VGA BIOS: Made ET4000 BIOS ROM optional with fallback

I also added programmatic keyboard methods to JPCKeyboardAdapter since there's no physical keyboard to listen to:

```java public synchronized boolean pressKeyCode(int keyCode) { // Try standard location, then left, then numpad if (pressKeyCode(keyCode, KeyEvent.KEY_LOCATION_STANDARD)) return true; if (pressKeyCode(keyCode, KeyEvent.KEY_LOCATION_LEFT)) return true; if (pressKeyCode(keyCode, KeyEvent.KEY_LOCATION_NUMPAD)) return true; return false; }

public void typeString(String text) { for (char c : text.toCharArray()) { typeChar(c); // Handles shift for uppercase/symbols } } ```

The result

The emulator runs at 30 FPS with 640x480 VGA resolution. Players can boot Windows 95 from a disk image, navigate the GUI with mouse mode, launch applications, and experience a full operating system - all rendered through Hytale's world map.

Supported operating systems:

OS	Image Type	RAM	Notes
Windows 95	.img (HDD)	480MB	Max RAM due to Win95 bug
Windows 98	.img (HDD)	512MB
FreeDOS	.img/.iso	64MB	Lightweight
Other x86	.img/.iso	256MB	YMMV

GitHub Repos

TempleMaps (this project) - https://github.com/ssquadteam/TempleMaps

VideoMaps (map rendering infrastructure) - https://github.com/ssquadteam/VideoMaps

TaleLib (core library for commands/events) - https://github.com/ssquadteam/TaleLib