TinyOS

TinyOS is a minimal, 32-bit x86 operating system implemented to get familiar with OS development internals. I made this for fun and exploration.

Specs

• Architecture: x86 (i386)
• Bootloader: 16-bit real-mode (NASM) -> 32-bit protected-mode.
• Kernel: Freestanding C (GCC).
• Video: VGA Mode 13h (320x200, 256 colors).
• Interrupts: IDT for hardware IRQs and CPU exceptions.
• Input: PS/2 keyboard.
• Shell: Basic CLI.

Implementation Details

• boot.asm: 16-bit real-mode bootloader.
• entry.asm: Protected-mode initialization and kernel entry.
• kmain.c: Main kernel loop.
• idt.c: IDT configuration and interrupt routing.
• keyboard.c: PS/2 scancode to ASCII mapping.
• shell.c: Basic CLI.
• link.ld: Memory layout definition.

Dependencies

• nasm
• gcc (i386 target support)
• binutils (ld with elf_i386 support)
• qemu-system-x86_64
• make

Usage

Build:

make

Run:

make run

Clean:

make clean

Memory Map

The kernel is loaded into memory starting at 0x1000. The VGA buffer for Mode 13h is located at 0xA0000.