My guess is that the Infocom game was setting up some sort of FP emulation TSR and not cleaning it up, and BattleTech was coincidentally using it. Or whatever t

My guess is that the Infocom game was setting up some sort of FP emulation TSR and not cleaning it up, and BattleTech was coincidentally using it. Or whatever the equivalent of a windows 3.x VxD is for OS/2, if that exists. Or just otherwise messing with the interrupt tables involved in the arcane x87 protocol in a way that un-breaks things. Also it looks like there may be some issues with FP/FP emulation on the OS/2 DOS extender host: https://www.os2museum.com/wp/floating-point-exceptions-and-dos-extenders/ https://www.os2museum.com/wp/floating-point-exceptions-and-d...