0000000002_ 🧠 VDOS Step 02 – Real Bootloader - MohammadMovi/VDOS GitHub Wiki

This step introduces a real bootloader written in 16-bit assembly language that is directly executed by the BIOS during system startup.

• Build a 512-byte bootable image (boot.img)
• Load it at memory address 0x7C00
• Display a message using BIOS interrupt int 0x10
• Halt the system

• Instruction set: x86 Real Mode
• Org origin: ORG 0x7C00
• Message stored in memory and printed via lodsb + int 0x10
• Boot signature 0xAA55 added manually to make image bootable

nasm -f bin boot.asm -o boot.img
qemu-system-x86_64 -drive format=raw,file=boot.img

You should see:

🟢 VDOS Booting Successfully!

• BIOS loading process

• Boot sector memory map

• x86 interrupts (int 0x10)

• Text printing without OS

→ Add keyboard input
→ Build a simple shell
→ Load files from floppy (FAT12-like structure)

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