Nostalgia OS

An x86_64 operating system kernel written in Rust.

Features

Core Subsystems

• Memory Manager (MM): PFN database, pool allocator, virtual address descriptors, user-mode page tables
• Object Manager (OB): Hierarchical namespace, handle tables, object types
• Process Manager (PS): Process and thread management, CID table
• I/O Manager (IO): IRP-based driver model, device and driver objects
• Security Reference Monitor (SE): SIDs, ACLs, tokens, privileges, access checks
• Configuration Manager (CM): Registry-style hives and keys
• Kernel Executive (KE): Scheduler, timers, APCs, DPCs, synchronization primitives

Hardware Support

• x86_64 architecture (GDT, IDT, TSS)
• UEFI bootloader
• LAPIC timer (1000 Hz)
• ATA/IDE disk driver
• Serial console (COM1)
• Framebuffer graphics

File System

• FAT32 driver with full read/write support
• VFS layer with mount point manager
• File operations: create, read, write, delete, rename, truncate, stat, sync
• Directory operations: mkdir, rmdir, readdir

Execution Model

• Ring 0 / Ring 3 separation
• SYSCALL/SYSRET for user mode transitions
• Priority-based preemptive scheduler (32 priority levels)
• Multi-object wait support (WaitForSingleObject, WaitForMultipleObjects)

Building

Prerequisites

• Rust nightly toolchain
• QEMU with OVMF (UEFI firmware)

# Install Rust nightly
rustup install nightly
rustup default nightly

# Install required components
rustup component add rust-src llvm-tools-preview

# Install QEMU and OVMF (Ubuntu/Debian)
sudo apt install qemu-system-x86 ovmf

Build

./build.sh

Run

./run-qemu.sh

Project Structure

NostalgiaOS/
├── boot/
│   └── uefi-loader/       # UEFI bootloader
├── kernel/
│   └── src/
│       ├── arch/          # Architecture-specific code (x86_64)
│       ├── cm/            # Configuration Manager (registry)
│       ├── fs/            # File systems (FAT32, VFS)
│       ├── hal/           # Hardware Abstraction Layer (APIC, ATA)
│       ├── io/            # I/O Manager (IRP, devices, drivers)
│       ├── ke/            # Kernel Executive (scheduler, sync)
│       ├── mm/            # Memory Manager
│       ├── ob/            # Object Manager
│       ├── ps/            # Process Manager
│       ├── rtl/           # Runtime Library
│       └── se/            # Security Reference Monitor
├── build.sh               # Build script
└── run-qemu.sh            # QEMU launch script

License

This project is for educational purposes.