MinimalOS NextGen

A capability-based microkernel operating system written from scratch in Rust for x86_64.

What is MinimalOS NextGen? #

MinimalOS NextGen is an educational operating system that prioritizes security and minimalism. The kernel provides exactly six services — everything else runs in userspace:

Service	Description
Address space isolation	Each process gets its own page tables
Capability enforcement	Unforgeable tokens control access to resources
IPC message delivery	Opaque bytes + capability transfers between processes
CPU time multiplexing	Tickless scheduler with per-core run queues
Interrupt routing	IRQs delivered to capability holders
Memory grant transfers	Zero-copy page sharing via capabilities

Drivers, filesystems, networking, and GUI all run as unprivileged userspace processes communicating through IPC — the kernel never implements policy.

Target Hardware #

The primary target is the HP 15-ay028tu laptop:

CPU: Intel Pentium N3710 — 4-core Airmont (Braswell), 1.6–2.56 GHz
RAM: 8 GB DDR3L-1600
GPU: Intel HD 405 (Gen8)
Storage: SATA HDD / replaceable with SSD
Boot: UEFI via Limine v8.6.0 bootloader

The OS also runs in QEMU with OVMF UEFI firmware for development and CI.

Design Philosophy #

Policy-free kernel — The kernel enforces mechanisms, never policy. Scheduling policy, filesystem layout, network protocols — all live in userspace.
Capability-based security — Every resource access requires an unforgeable capability token. No ambient authority, no root user.
Rust all the way — The entire kernel and userspace are written in Rust, leveraging the type system and ownership model for memory safety.
Minimal trusted computing base — Only ~22 syscalls. The smaller the kernel, the less surface area for bugs.

Current Status #

📝 Note

MinimalOS NextGen is under active development. Sprints 1–9.5 are complete; Sprint 10 (Wasm Hypervisor) is in progress.

Sprint	Focus	Status
Sprint 1	Boot & Serial Output	✅ Complete
Sprint 2	Memory Management	✅ Complete
Sprint 3	Interrupts & Exceptions	✅ Complete
Sprint 4	Processes & Scheduler	✅ Complete
Sprint 5	Capabilities & IPC	✅ Complete
Sprint 6	Syscall Interface & Userspace	✅ Complete
Sprint 7–9	Init, Delegation & The God Process	✅ Complete
Sprint 9.5	Reaper & Resource Teardown	✅ Complete
Sprint 10	Wasm Hypervisor (Ring 3 Allocator)	🔄 In Progress

See the full Roadmap for details.

Quick Start #

# Clone and build
git clone https://github.com/nadeeshafdo/MinimalOS.git
cd MinimalOS
make

# Create bootable ISO and run in QEMU
make run

See Getting Started for prerequisites and detailed instructions.