Well, your friend should keep a closer eye to the research literature ;) A number of projects have been launched to create smaller, leaner OS kernels. This is

Well, your friend should keep a closer eye to the research literature ;) A number of projects have been launched to create smaller, leaner OS kernels. This is particularly important in HPC applications as the kernel is a primary source of latency in computation. One of the major works in this area is (shameless plug) Kitten OS[1], which is a stripped down Linux kernel meant mainly for HPC. However, I don't think recreating or hacking on Kitten is a good task for someone who wishes to learn kernel programming, Rust, or both. The best way to learn how something works is to remake it yourself. [1] https://software.sandia.gov/trac/kitten https://software.sandia.gov/trac/kitten