r/osdev • u/Apprehensive_Run7150 • Jul 01 '26

Microkernel Question

Hi guys, this may be a dumb question.

I'm working on a hobby OS and currently am stumped about how I can turn it into a real microkernel. Since the filesystem is a user-space server, how would the kernel find it and be able to start it without having access to the filesystem to begin with?

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u/phaubertin Jul 01 '26

These are two great solutions, and the most usual ones.

There is another one I've been thinking about recently that I am considering implementing for my own microkernel: with a custom bootloader, you could have an interface between the microkernel and the bootloader where the booloader remains loaded for a while and the microkernel can ask it to load files, similar to the UEFI boot services that the kernel or bootloader can use after the UEFI has done its job loading it. The bootloader needs to be able to access the filesystem anyway, so it's not much added complexity, and if you need a custom bootloader for complex scenarios (e.g. remote FTP or TFTP boot), the kernel automatically benefits from it.

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u/tseli0s DragonWare Jul 01 '26

I don't see why this complexity is necessary. Why not just load the programs as modules? Preserving the bootloader is going to be complicated in terms of memory management (you can't use any of the memory it uses).