Don’t waste money on a math coprocessor they said
 

One thing I had stumbled upon was that if I launched an ancient Infocom game in a DOS box, and then launched BattleTech it had a much higher chance of running. But this did not always equate to it working. How is launching an old COM file from the early 80’s excise the ‘devil’ of some 1988 EXE from running?

https://www.osnews.com/story/137838/...sor-they-said/