Indeed, e.g. Apple Lisa OS and the first Mac OS. But the present one so far is only around 100 lines; the author calls it a "bootloader". Here is a list of more

Indeed, e.g. Apple Lisa OS and the first Mac OS. But the present one so far is only around 100 lines; the author calls it a "bootloader". Here is a list of more complete systems: https://wiki.freepascal.org/Operating_Systems_written_in_FPC https://wiki.freepascal.org/Operating_Systems_written_in_FPC.