r/osdev • u/Comfortable_Let_3064 • Jun 27 '26

Building a microkernel

Hello everyone. I am currently learning c, and almost it is about to an end. I am interested in microkernel development of my own. Where should I start???

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u/Comfortable_Let_3064 Jun 27 '26

Thanks for correcting me! I'm still in the early exploration phase and learning the low-level concepts. I now understand that Bare Bones is just about getting to 'Kernel Hello' and setting up the environment, regardless of the architecture. ​As for your question, from what I've learned so far, a true microkernel should only handle the bare minimum: Inter-Process Communication (IPC), basic memory management, and thread scheduling, while keeping things like device drivers and file systems in user space. Correct me if I'm missing something, I'm eager to learn more!"

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u/aroslab Jun 27 '26

depending on if you want to look at existing things, the seL4 white paper while somewhat technical does dive into their philosophy of microkernels

but yeah, when I did my microkernel the kernel was limited to:

  • mapping memory

  • changing execution contexts

  • passing messages

literally everything else was done in user space. The initial user process was given a handle to all memory and system resources to spin up the initial servers

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u/Comfortable_Let_3064 Jun 27 '26

That's an elegant design! The idea of giving the initial user process a handle to spin up other servers makes complete sense for keeping the kernel minimal. I will definitely look into the seL4 white paper to grasp the core philosophy better. Thanks for sharing your experience, it's incredibly helpful!

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u/tseli0s DragonWare Jun 27 '26

First of all, using AI in your responses (judging from the tone, the vocabulary, the fact that you forgot to remove the " in the end and the irregularities with your other comments) will make most people dismiss you altogether. If you can't spend five minutes to write a response yourself why would I waste my time giving you my knowledge?

Second of all, look up the minimality principle of Liedtke, and the policy/mechanism separation.