I built a microkernel from scratch in Rust (5-part series: boot, IPC, preemption, virtual memory)

Posted by amitbahree@reddit | programming | View on Reddit | 16 comments

I had some free time between jobs and finally did something I’d wanted to do for years: build an OS kernel from scratch.

I mostly work in AI/ML these days, but I wanted to revisit the fundamentals and better understand what’s underneath the abstractions we use every day.

So I built a small microkernel in Rust and documented the journey.
By the end, it boots on an emulated ARM machine, handles task communication, supports preemptive scheduling with interrupts, and enables virtual memory with page tables + MMU.

The most interesting takeaway for me: modern systems concepts feel “magical” until you build even a minimal version yourself. Then you realize they’re just layers of careful engineering and tradeoffs.

Start here (Part 0): https://blog.desigeek.com/post/2026/02/building-microkernel-part0-why-build-an-os/

GitHub repo: https://github.com/bahree/rust-microkernel

Part 0 has links to the full 5-part series at the top and bottom if you want to follow the whole build from boot to virtual memory.

I’m not an OS expert, just sharing what I learned in case it’s useful to other curious devs. 😊

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programming-ModTeam@reddit

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This content is very low quality, stolen, or clearly AI generated.

Relative-Scholar-147@reddit

Sloop, nothing interesting on the article good luck promoting yourself the same way million other losers do.

No content written mostly by an LLM. If you don't want to write it, we don't want to read it.

jefwillems@reddit

Just so you know, the prev and next buttons are reversed at the bottom of your site

singron@reddit

You might want to mark the x86 support as unfinished somewhere. I'm more familiar with x86 so I was browsing that part of the code, and it was essentially entirely empty, and the bootloader just uses the bootloader_api crate.

All the interesting code is in arch_aarch64_virt.

I think this was probably fun and it seemed like you probably learned a lot, but I'm not sure I would call this a microkernel. It's really a bunch of independent bare-metal demos.

E.g. if you wanted to write 2 tasks that communicate with IPC, have their own virtual memory spaces, and use preemption, you would have to abstract and combine the functionality from a bunch of demos that are currently separate. The IPC demo and the preemption demo have completely different schedulers (both oblivious to the MMU), and the page table demo has no scheduler, so using all 3 features at the same time would require writing a new scheduler that combined IPC and preemption while switching page tables for different tasks.

rescuemod@reddit

"I write..." Take a look into .gitignore *Found .claude/ & .cursor/"

🫩

bobsbitchtitz@reddit

I was expecting slop but this is pretty cool

amitbahree@reddit (OP)

Thank you 🙏. If only folks actually went and read the series. 🙃

This is a totally malformed link.

You just want the text:

LevelIndependent672@reddit

ipc with no buffering works great in demos and breaks the second you actually need it. thats how you learn why queues exist ngl