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Aeolos OS

A little x86_64 hobby operating system built from scratch in C and Assembly.

x86_64 Architecture

Native 64-bit support with modern CPU features

Stivale2 Boot Protocol

Clean bootloader interface via Limine

Memory Management

Physical and virtual memory with paging

Multiprocessing

Symmetric multiprocessing (SMP) support

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Overview

Aeolos is an educational operating system project that implements core OS functionality from the ground up. It demonstrates low-level system programming concepts including:
  • Boot Process: Uses the Stivale2 boot protocol via the Limine bootloader
  • Memory Management: Complete physical memory manager (PMM) and virtual memory manager (VMM) with paging
  • Hardware Support: ACPI, APIC, HPET timer integration
  • Multitasking: Preemptive multitasking with scheduler
  • Virtual Filesystem: Unified VFS interface with ramfs and ttyfs implementations
  • I/O: Serial port and framebuffer output with terminal emulation

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Key Features

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Hardware & Architecture

  • x86_64 (64-bit) architecture support
  • CPU feature detection and initialization
  • Global Descriptor Table (GDT) setup
  • Interrupt Descriptor Table (IDT) management
  • Physical Memory Manager (PMM) with buddy allocator
  • Virtual Memory Manager (VMM) with page tables
  • Bootloader memory reclamation
  • Memory mapping utilities (PHYS_TO_VIRT conversion)
  • Symmetric multiprocessing (SMP) initialization
  • Per-CPU APIC configuration
  • 16-bit real mode trampoline for AP startup
  • Multi-core scheduler support
  • ACPI table parsing (RSDP, MADT, HPET)
  • Local APIC and I/O APIC support
  • HPET (High Precision Event Timer) driver
  • Framebuffer and serial I/O

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Software Features

Virtual Filesystem

Unified VFS layer with ramfs for in-memory files and ttyfs for device access

Multitasking

Preemptive scheduler with task creation and management

Initrd Support

Compressed initial ramdisk loaded at boot (SAF format)

Terminal

Text-mode terminal with serial and framebuffer output

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System Initialization

The kernel follows a structured initialization sequence in kmain() at startup: 
// From kernel/kmain.c
_Noreturn void kmain(stivale2_struct* info)
{
    // Convert physical bootloader address to virtual
    bootinfo = (stivale2_struct*)PHYS_TO_VIRT(info);

    klog_printf("Aeolos x86_64 (alpha)\n");
    klog_printf("Built on "__DATE__" at "__TIME__".\n\n");

    idt_init();
    cpu_features_init();

    // Memory management
    pmm_init((stv2_struct_tag_mmap*)stv2_find_struct_tag(bootinfo, STV2_STRUCT_TAG_MMAP_ID));
    vmm_init();
    gdt_init();

    // I/O initialization
    fb_init((stv2_struct_tag_fb*)stv2_find_struct_tag(bootinfo, STV2_STRUCT_TAG_FB_ID));
    serial_init();
    term_init();

    // System hardware
    acpi_init((stv2_struct_tag_rsdp*)stv2_find_struct_tag(bootinfo, STV2_STRUCT_TAG_RSDP_ID));
    hpet_init();
    apic_init();
    vfs_init();
    smp_init();

    // Reclaim bootloader memory
    pmm_reclaim_bootloader_mem();

    // Start multitasking with kinit as first task
    sched_init(kinit);

    while (true)
        ;
}
Aeolos is currently in alpha stage. Some features like usermode support, disk drivers, and keyboard/mouse input are still under development.

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Project Status

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Completed Features

  • ✅ x86_64 long mode with higher-half kernel
  • ✅ Stivale2 boot protocol integration
  • ✅ Physical and virtual memory management
  • ✅ SMP initialization and multi-core support
  • ✅ ACPI/APIC/HPET hardware abstraction
  • ✅ Multitasking with preemptive scheduler
  • ✅ Virtual filesystem framework
  • ✅ Serial and framebuffer output
  • ✅ Initrd loading and decompression

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In Progress

  • 🚧 Usermode support (partial)
  • 🚧 Virtual filesystem (partial - ramfs and ttyfs working)
  • ⏳ Disk drivers
  • ⏳ Mouse and keyboard drivers

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Next Steps

Try Aeolos

Download and run Aeolos in QEMU

Build from Source

Compile the OS yourself

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