Northport is a monolithic kernel, written in C++ and booted via the Limine protocol. It currently supports x86_64 and riscv64 machines. This repo also contains a completely standalone support library (see libs/np-syslib).
Instructions for building it yourself are available here, and a more in-depth manual can be found under the releases tab or by cloning this repository and running make docs.
A brief summary of the current goals and features are listed below, or check the roadmap for a more granular view. Pre-built isos are made available at major feature milestones, but for the latest and greatest it's recommended to build from the master branch.
- To build a usable, extensible and relatively complete kernel. This means an smp-aware scheduler with support for heterogeneous processors, media stacks (graphics, audio and network) and a flexible driver infrastructure.
- Support for multiple architectures: the current targets are x86_64 and riscv64, but this may expand over time.
- Be self hosting, this includes cross compiling the system.
- Clean code and useful documentation.
- Usable on both virtual machines and real hardware.
An extended goal (previously goal #5) is to add a comfortable user experience: a window manager, basic programs like a text editor and file explorer.
Kernel:
- Support for multiple architectures: riscv64, x86_64.
- Memory management:
- Hybrid PMM, freelist for single page allocations and a slow path for allocations with constraints.
- Modular and portable VMM, with demand paging options for anon and vfs backed memory. Inspired by the old SunOS design.
- General purpose heap provided by slabs for smaller objects and a freelist for larger objects. Slab allocation can be accelerated by core-local caches, and several debug features are available.
- Time management:
- Global software clock, driven by a number of hardware timers: LAPIC, TSC, HPET, PIT, SBI timer.
- Run levels, allowing kernel to selectively mask groups of interrupts and prevent execution being hoisted by the scheduler. This also means support for DPCs and APCs.
- Scheduler with core-local and shared work queues, and work stealing.
- Waitable events, with support for cancelling, timeouts and waiting on multiple events at once.
- Filesystem:
- File contents and metadata are sparsely cached in memory as needed. VFS nodes can also be destroyed and re-created as needed.
- Robust tempfs driver provided within the kernel.
- Drivers:
- Loaded (and dynamically linked) on-demand, based on load conditions described in driver metadata.
- Drivers, device descriptors and device APIs are organised in a tree, allowing parent drivers to provide functionality to child drivers and device nodes.
- Dedicated driver API functions, based on C-language API for the target platform - meaning drivers can be written in any language, although all first-party drivers are C++.
- Debugging:
- Lock-free logging infrastructure, with per-core log buffers for maximum speed. Support for early log outputs via simple devices like uart chips or the built-in graphical terminal (based on gterm for Limine).
- UB sanitizer, helpful for catching bugs or increasing code size.
- Stack walker and symbol lookup, including symbols of loaded drivers. De-mangling C++ names not currently supported.
Build System:
- Uses stock core tools and GNU make, runs anywhere (tm).
- Xorriso is needed for generating bootable isos.
14/02/2024: Status bar showing virtual memory and driver statistics
14/02/2024: Device node tree being printed shortly after adding the IO manager.
Older Screenshots
11/10/2023: Kernel panic while loading a malformed driver from the initdisk.
20/11/2022: x86 and riscv kernels running side by side in qemu.
- DreamOS64: another 64-bit OS by one of the northport contributors, Ivan G.
- OSdev notes: a repository of notes about various osdev topics. Feel free to contribute!
This is a complete rewrite of the original. If you're looking for that, it's available on the archive-2022-version branch.
