It is, of course, a very simple system if you never plan to render anything that isn't an ASCII character, or a value in US dollars. Things get complicated pretty quickly in DOS/Windows world once you wander outside the ASCII character set range. And there are strange and wonderful things in EGA and VGA hardware (standard, non-standard, and outright genius-level hackery) that are ridiculously complicated that are hardly ever used if you are fortunate enough to be an American who never uses anything but DOS.