There were also files and buffers to contend with in autoexec.bat iirc.Aarrr, Upper Memory Block!!! I remembered this line in the dos config (config.sys?)
I actually don't know the details behind the scene, I just tried to remember which config is needed for specific game then mix and match them in the mutli-boot floopy. That was fun!!!
But my computing (lack of) knowledge goes back further than that