The bootOS operating system is a monolithic operating system that fits in one boot sector and can run on the original IBM PC. It is capable of loading, executing, and saving programs and has a filesystem. It can work with any floppy disk size starting at 180K and provides services such as input keys, output characters, and file load/save/delete. It uses tracks from 0 to 32 and sector 1, with a directory contained in track 0 and side 0. In addition to the operating system, bootOS offers a variety of programs such as cubicDoom, bricks, and bootBASIC. A programming book and additional games are also available.
https://github.com/nanochess/bootOS