Oh yeah, this is right up my alley. I've been thinking about making a Forth on bare metal for a while (made a Forth interpreter in C last summer, and a tiny amount of testing stack manipulation in hand-assembled machine language on a C64U), and the thought I (coincidentally) had moments before seeing this link was about making a boot sector on some floppies I just got for my 8088 IBM PC. I know that will only work for the Real Mode part but it might be fun to start there anyway. Edit: I knew about CollapseOS but didn’t realize this had been around too.