Really, crazily enough, if you want stability in older computers, you just can't beat DOS.
DOS OK as long as you only wanted to address a total 1MB or ram one 64K segment at a time.
Once you tried to address over 1MB of ram through various extended and expended memory schemes, or enter "386" 32bit mode stability went out the window. Those memory managers were massively temperamental when trying to optimize your valuable "conventional" RAM.
If you want to real treat, you could add in a splash of multitasking with various DOS extenders like Desqview windows 3X

I can't imagine Amiga being any less stable than that mess
