[ReaLNero]

I've always been interested in writing my own Unix-like kernel! Could you share what resources you used to write it? How long did the whole thing take?

Just to understand the scope of the work, did you implement any of the following: memory isolation, networking, concurrency via interleaving on single thread, parallelism where n threads can run n processes simultaneously? How long did each take to get done?

[rajeevk]

I did this while I was doing my bachelor degree course. It was four year course and I started doing this sometime in 2nd year and continued till 4th year. I was not always writing code as I had to study other subjects as well. Also I was just learning coding and other computer science concepts, so it was like learning and writing code. But the writing the kernel forced me to learn many computer science concepts very deeply.

At the end, what I had was a kernel which could boot on bare metal (or VM) and provided a command line interface. It had a virtual file system layer and ext2 file systems, process management (fork, exec sys call), memory management (paging and process isolation) and device drivers for keyboard and hard disk. The kernel was able to fork and exec static ELF binary.

I did not reach to networking and threading. But that was next step which could make it complete unix kernel.

I implemented in bits of assembly(nasm) and C++. So I had to learn runtime and code generation aspect of c++. Based on that learning I wrote this articles on c++ object models and other internals. https://www.avabodh.com/cxxin/cxx.html