Beautiful Boot for PC

A bare-metal 8086/8088 bootloader and game launcher, inspired by the legendary 1984 "Beautiful Boot" on the Apple II by Mini Appler of the Midwest Pirates Guild.

Experience the original Apple II Beautiful Boot Disk Utility: 👉 HERE

Experience the original Apple II Beautiful Boot Game Disk: 👉 HERE

Like its Apple II ancestor, Beautiful Boot for PC renders an animated falling starfield — automatically adapting to VGA (Mode 13h, 256 colors), EGA (Mode 0Dh, 16 colors), or CGA (Mode 04h, 4 colors) based on the detected graphics card. It scans a standard FAT12 floppy, lets you browse .com, .exe, and .bin executables, and boots them in a bare-metal DOS-compatible environment.

Upon program exit, the menu restores the graphics environment for the detected adapter and returns to the selection screen.

Experience Beautiful Boot for PC — v86 Edition: 👉 HERE

Experience Beautiful Boot for PC — js-dos Edition (AdLib Audio): 👉 HERE

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Features

• Standard FAT12 Compatibility: Formatted as a real FAT12 1.44 MB floppy disk. Preserves the BIOS Parameter Block (BPB) on Track 0, Sector 1, so the image remains fully accessible by modern OS utilities (e.g. mtools or standard mounting).
• Modular Stage 2: Stage 2 is stored as a normal file (stage2.bin) in the FAT12 filesystem. The Stage 1 boot sector dynamically searches the Root Directory for "STAGE2 BIN" and loads it via the FAT12 cluster chain, ensuring robust loading even if the file is fragmented or non-contiguous.
• VFAT LFN (Long File Name) Support: Fully parses and reconstructs standard VFAT long filenames (LFN) created by tools like mtools (mcopy) or natively by Windows 95 and later. Implemented in pure 16-bit real mode, it dynamically matches LFN entries with their corresponding 8.3 Short Filenames (SFN) using checksum validation, preserving original spaces and mixed-case names (e.g., Agent USA.exe, King's Valley.exe) with seamless SFN fallback.
• Dynamic File Explorer & Error Handling: Auto-scans the root directory of the active drive (A: or B:) and displays up to 15 matched files per page (mapped from A to O) along with their sizes in Kilobytes (K) (e.g. 042K ). Hides system files like stage2.bin. If a drive has no disk or encounters a read error, the loader gracefully displays "No Disk Inserted / Disk Error" and shows "???? Free sectors" in the footer.
• Customizable Footer Comments: Configurable at build time through build.sh prompts. Allows compiling custom messages (up to two 40-character lines) directly into the bootloader footer.
• Multiple Video Modes & Hardware Mappings: Pressing TAB cycles between monochromatic Green, monochromatic Amber (retro CRT amber screen feel), and Multi-color (the default boot mode) modes. The bootloader dynamically maps the text and star colors to fit the active display adapter:
  • VGA (Mode 13h): Renders a beautiful 256-color palette (e.g. customized NTSC Amber and deep orange separator).
  • EGA (Mode 0Dh): Maps colors to standard high-intensity 16-color palette elements (e.g. Yellow and Brown for Amber).
  • CGA (Mode 04h): Dynamically toggles hardware Palette 0 (Green/Red/Brown) for Green/Amber modes and Palette 1 (Cyan/Magenta/White) for Color mode via BIOS interrupt INT 10h / AH=0Bh to avoid monochrome text rendering in incorrect colors.
  • MDA / Hercules: Automatically falls back to standard 80x25 text mode (Mode 03h) since standard PC BIOS does not natively support graphics modes or pixel-drawing routines on monochrome adapters, ensuring maximum hardware compatibility and safety.
• Multi-Adapter Graphics, Starfield & Audio: Renders a vertical falling starfield at ≈60 FPS (synchronized with the video card's vertical blanking interval to prevent tearing) using custom 8x8 font rendering. We offset the starfield trajectories to the character cell spacing columns so stars fall cleanly between text columns without clipping any glyph pixels. Each star movement fires a crisp 2.5 ms PC speaker click at a randomly varied pitch (~340–1136 Hz), producing a dense Geiger-counter-like crackling — faithfully recreating the Apple II's signature starfield audio signature.
• Star Speed Customization & OSD: Pressing +/= or -/_ adjusts the background starfield speed dynamically from level 01 to 12. Adjusting the speed displays an OSD indicator (Star Speed: 01 ~ Star Speed: 12) matching the theme color on the bottom separator line, which automatically fades out after 1 second of inactivity. Speeding up the stars naturally increases the click frequency for a higher-energy retro sound.
• Curtain Closing Transition & Sound: When loading a program, the screen closes like a curtain from the top and bottom simultaneously. During this animation, the PC speaker plays a sweeping laser frequency pitch synchronized with the collapsing rows. Upon completion, the system switches to 80x25 text mode, displays a centered "Prepare Yourself..." screen message on row 12, and pauses for 1 second before executing the binary.
• Robust MZ (.EXE) Relocator: Parses the DOS MZ header, copies the program code block, zeros the PSP, relocates segment pointers based on the actual header geometry, and sets up registers and stack space.
• COM & BIN Program Support: Standardizes COM environments by setting up the PSP at 0x1000:0000, copying code to 0x1000:0100, zeroing registers, and setting the stack pointer to 0xFFFE.
• Pure 8086 Instruction Set: Restricts assembly instructions to the original 8086/8088 instruction set (no movzx, no immediate shifts > 1, no FS/GS registers).
• Interactive Controls:
  • A–O: Load and execute the corresponding program on the current page.
  • TAB: Cycle video color mode (Green -> Amber -> Color -> Green).
  • SPACE: Swap boot drives (e.g. floppy A: vs B:).
  • ENTER: Toggle to the next page of the file directory.
  • + or =: Increase the falling star speed (levels 01 to 12).
  • - or _: Decrease the falling star speed (levels 01 to 12).
  • ESC: Exit and drop to ROM BASIC via BIOS INT 18h.

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Memory Map

The bootloader reserves a clean 64 KB block (linear 0x0000–0xFFFF). Everything from 0x1000:0000 (linear 0x10000) onward is left entirely free for DOS programs, providing 576 KB of contiguous conventional memory.

Bootloader Region (64 KB — linear 0x0000–0xFFFF)

Linear Address	Seg:Off	Size	Description
0x00000–0x003FF	0000:0000	1 KB	Interrupt Vector Table (IVT)
0x00400–0x004FF	0000:0400	256 B	BIOS Data Area (BDA)
0x00500–0x006FF	0000:0500	512 B	Free / BIOS scratch
0x00700–0x022FF	0070:0000	7 KB	Root Directory buffer (14 sectors × 512 B)
0x02300–0x034FF	0230:0000	4.5 KB	FAT buffer (9 sectors × 512 B)
0x03500–0x05D85	0350:0000	~10.1 KB	Stage 2 code + resident handlers (INT 21h + bounce buffer)
0x05D86–0x07BFF	—	~7.6 KB	Contiguous Free Space
0x07C00–0x07DFF	0000:7C00	512 B	Stage 1 boot sector (BIOS-mandated, one-shot)
0x07E00–0x07FFF	0070:7700	512 B	Bootloader stack (grows downward from 0x07900 / 0x08000 linear)
0x08000–0x0FFFF	—	32 KB	Free memory below program space

Program Region (576 KB — linear 0x10000–0x9FFFF)

Linear Address	Seg:Off	Size	Description
0x10000–0x100FF	1000:0000	256 B	Program Segment Prefix (PSP)
0x10100–0x9FFFF	1010:0000	~575 KB	Program code, heap, and stack

MZ (.EXE) Loader & Relocation Strategy

When an EXE file is selected, the relocator (exe_reloc.asm) behaves exactly like MS-DOS loader:

1. Loads the raw executable file directly into segment LOAD_SEG from the FAT12 cluster chain (processed at LOAD_SEG + header_paragraphs to avoid overlaps).
2. Checks the MZ signature (0x5A4D) to verify the EXE format.
3. Reads the header parameters (relocation table offset, item count, header size, stack registers SS:SP, and entry registers CS:IP).
4. Dynamically calculates the executable's image size from the MZ header (pages * 512 + last_page_bytes - header_size).
5. Copies the program code (skipping the header) down to LOAD_SEG:0000.
6. Zeroes out the 256-byte PSP block at PSP_SEG:0000 and configures termination hooks (INT 20h exit call at PSP:0).
7. Applies relocation offsets. For each entry in the relocation table:
   • Finds the absolute target address: (LOAD_SEG + reloc_segment) : reloc_offset.
   • Modifies the segment word at that address by adding the base load segment LOAD_SEG.
8. Restores initial stack segment (LOAD_SEG + SS) and stack pointer (SP).
9. Clear all general-purpose registers (AX, BX, CX, DX, SI, DI, BP) to 0.
10. Far-jumps to CS:IP (relative to LOAD_SEG) to start the program.

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More than just a bootloader and file launcher — it's a minimal DOS!

Minimal DOS API (INT 21h) Support

To enable standard DOS executable games to run in a standalone bare-metal environment, the bootloader installs a resident minimal INT 21h handler. This provides emulation for essential DOS system calls:

• Program Termination:
  • AH = 4Ch (Exit with return code): Emulated by triggering a software reboot (INT 19h) to return the user gracefully back to the boot menu.
• Console Input/Output:
  • AH = 01h (Read character with echo)
  • AH = 02h (Character output)
  • AH = 06h (Direct console I/O): Supports raw character output and non-blocking keyboard input with Zero Flag status reporting.
  • AH = 07h / 08h (Read character without echo): Blocking keyboard read via BIOS INT 16h.
  • AH = 09h (Print string): Outputs '$'-terminated strings to the screen.
  • AH = 0Bh (Check input status): Returns AL = 0xFF if key is pending, 0x00 if none.
  • AH = 0Ch (Clear buffer and input): Emulates clearing keyboard buffer and executing sub-functions.
• Resident FAT12 File Operations Subsystem (with Subdirectory Isolation):
  • AH = 3Ch (Create File): Creates or truncates a file inside the current game's directory, allocating starting clusters.
  • AH = 3Dh (Open File): Opens an existing file, mapping it to a file handle slot.
  • AH = 3Eh (Close File): Closes the file handle, flushing dirty sectors and updating size in the directory.
  • AH = 3Fh (Read File): Reads file data byte-by-byte by walking the FAT12 cluster chain.
  • AH = 40h (Write File): Writes data, dynamically appending and allocating FAT12 clusters as the file grows.
  • AH = 41h (Delete File): Deletes the file entry and releases all associated FAT12 cluster chains.
  • AH = 42h (Lseek): Modifies the active file pointer location (SEEK_SET, SEEK_CUR, SEEK_END).
  • AH = 43h (Get/Set Attributes): Returns file attributes (e.g. read-only, hidden, archive).
  • Subdirectory Isolation: All file operations are dynamically mapped to the cluster chain corresponding to the program's parent directory (current_dir_cluster). This lets each game (e.g., Goonies, Joust VGA, Hard Hat Mack) save configurations, high scores, and savegames (like GOON01.SAV inside ::goonies/) locally inside its own directory, keeping the disk's root directory perfectly clean and preventing FAT12 root directory entry exhaustion.
• System Information & Time:
  • AH = 30h (Get DOS Version): Returns DOS 5.0 to satisfy compiler startup code (e.g. Borland C++, Turbo C).
  • AH = 2Ch (Get Time): Dynamic time polling based on BIOS system ticks (INT 1Ah) to prevent timer/random-seed deadlock loops in games.
• Interrupt Vector Management:
  • AH = 25h (Set Vector): Updates the Interrupt Vector Table (IVT) in real mode.
  • AH = 35h (Get Vector): Reads segment and offset addresses from the IVT.
• Memory Management:
  • AH = 62h / 51h (Get PSP Segment): Returns the active PSP segment 0x1000.
  • AH = 48h (Allocate Memory): Implements segment-paragraph allocation from a dynamic free-memory allocator starting at the program's end (up to 640 KB conventional memory limit).
  • AH = 49h (Free Memory): Simulates memory deallocation.
  • AH = 4Ah (Resize Memory Block): Returns success to allow executable headers to allocate heap and stack space freely.

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Build and Run

Dependencies

The build environment runs on Ubuntu (or Windows WSL):

• nasm: Netwide Assembler
• make: Build automator
• mtools: Utilities to access FAT floppy images (mcopy, mdir)
• dosfstools: FAT filesystem utility (mkfs.fat)
• python3: Used to package .jsdos bundles for the js-dos web edition
• python3 -m http.server: Built-in HTTP server for local testing

On Ubuntu/WSL, running ./build.sh or make will check dependencies, compile the binaries, automatically search the games/ directory recursively for any game executables (.com, .exe, .bin), and package them into the floppy disk image in lowercase.

During compilation, the script emulates the interactive CLI interface of the original 1984 Apple II "Beautiful Boot" Disk Maker by MPG, displaying retro information layouts and prompting the user to customize the bottom two lines of the bootloader title page.

Compilation

Build the bootable floppy image and js-dos web bundles:

chmod +x build.sh
./build.sh

This produces three output files:

File	Description
beautiful.img	Bootable 1.44 MB FAT12 floppy image (for QEMU / real hardware)
beautiful-xt.jsdos	js-dos bundle — XT speed (cycles=fixed 800) for classic DOS games
beautiful.jsdos	js-dos bundle — Full Speed (cycles=max) for MSX-recompiled games

Alternatively, to build without the interactive prompts:

make

Emulation

v86 Edition (CPU-cycle accurate, PC Speaker audio)

Test the bootloader inside the browser via the embedded v86 emulator:

chmod +x test.sh
./test.sh

The test script will automatically open your default web browser to http://localhost:8000 and start a local Python HTTP server. The v86 emulator runs the floppy disk image (beautiful.img) directly in the browser with full Web Audio PC Speaker support!

The Web Emulator interface also includes built-in CPU Speed Throttling Controls (ranging from 1% to 100%). This allows you to slow down the emulated processor for older CPU-bound DOS games (such as Hard Hat Mack or Joust VGA) to make them playable and controllable, utilizing a jitter-free virtual clock and message-level synchronization to maintain a smooth 60 FPS visual frame rate even at ultra-low speeds.

js-dos Edition (Full AdLib / Sound Blaster audio)

The jsdos.html page runs the same floppy disk image inside js-dos (DOSBox-X WebAssembly), providing hardware-accurate AdLib OPL3 FM Synthesis and Sound Blaster 16 audio emulation — something the pure-JavaScript v86 emulator does not support.

Two speed modes are available via the toolbar dropdown and are persisted in localStorage:

Speed Mode	Bundle loaded	Best for
Speed: XT (800)	beautiful-xt.jsdos	Classic DOS games (e.g. Donkey Kong, Hard Hat Mack)
Speed: Full Speed	beautiful.jsdos	MSX-recompiled games (e.g. Friends Software titles)

Install to Real Hardware

To write the bootable image interactively to a physical 1.44 MB floppy disk or USB drive:

chmod +x install.sh
./install.sh

install.sh will:

1. Detect and list all removable/USB devices
2. Let you select the target drive
3. Confirm before writing (requires typing YES)
4. Write the image with dd and sync

USB Tip: Set your BIOS boot order to USB-FDD (USB Floppy) rather than USB-HDD for best compatibility with the 1.44 MB image format.

Or write manually if you know your device path:

sudo dd if=beautiful.img of=/dev/sdX bs=512 conv=fsync status=progress

(Replace /dev/sdX with the destination drive identifier of your disk)

Hardware Supported

• CPU: Intel 8086 / 8088 or 100% compatible processor.
• Memory: Minimum 256 KB RAM.
• Display Adapter:
  • VGA (or newer): Runs in Mode 13h (320x200, 256 colors) with full NTSC Amber/Color palette.
  • EGA: Runs in Mode 0Dh (320x200, 16 colors) with mapped Yellow/Brown Amber palette.
  • CGA: Runs in Mode 04h (320x200, 4 colors) with dynamic BIOS Palette 0/1 switching.
  • MDA / Hercules: Falls back to 80x25 monochrome text mode (Mode 03h) for safety.
• Floppy Drive: Standard 1.44 MB floppy drive (supports A: and B: with BIOS disk controller resets).

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Project Structure

beautifulboot-pc/
├── boot.asm             # Stage 1 bootloader (preserves BPB, loads Stage 2)
├── stage2.asm           # Stage 2 menu, starfield animation, FAT12 reader
├── exe_reloc.asm        # DOS MZ (.EXE) relocator & PSP builder
├── font.inc             # Custom 8x8 monochrome retro graphics font
├── gen_font.ps1         # PowerShell script to generate font.inc from font image
├── Makefile             # Build automation (make / make clean)
├── build.sh             # Interactive build script with retro CLI prompts
├── test.sh              # Rebuilds the image and serves locally for browser testing
├── install.sh           # Writes beautiful.img to a real floppy or USB drive
├── index.html           # v86 Edition web emulator page
├── jsdos.html           # js-dos Edition web emulator page (AdLib audio)
├── beautiful.img        # Built FAT12 floppy disk image
├── beautiful.jsdos      # js-dos bundle — Full Speed (cycles=max)
├── beautiful-xt.jsdos   # js-dos bundle — XT speed (cycles=fixed 800)
└── games/               # Subdirectory containing retro game binaries

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Tribute & In Memoriam

This PC port of Beautiful Boot is created as a humble tribute to the original Apple II program and its author, Matthew Dornquast (Mini Appler of the Midwest Pirates Guild / MPG), who passed away in 2022.

Beautiful Boot was a masterpiece of disk utility software that served as a fast boot launcher utility to load programs speedily and save time in the 1980s. This project aims to preserve that spirit and share the magic of its falling starfield and clicky crackle sound with retro-computing enthusiasts on the PC platform.

For those wishing to learn more or leave their thoughts, memorial posts and media can be found here: 👉 Matthew Dornquast Memorial Post (Apple II Enthusiasts Group) 👉 Jason Scott's Memorial Tweet (X) 👉 Beautiful Boot Audio Introduction / Podcast (YouTube)

Rest in peace, Matthew. Your code and legacy live on.

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Disclaimer

Although this program is space-themed, SpaceX did not sponsor this project! ;D

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License

This project is released under the Public Domain (CC0). Feel free to modify, distribute, or use it for any retro-computing projects.