Question: isn't printf a C standard library function? How can it be used in an OS with no cstdlib (yet)? Or, is the code in the article 'just a guideline'?
I don't know any Korean, but the difference in Japanese is that you (generally) don't address people with kōhai. The younger one usually says '<name>-senpai' or 'senpai', the elder just '<name>'.