Keatah

Kind of like that old PC programming book I had back in the 90's (That was old in the 90s!) where it recommended programmers to use text mode because "most PCs don't support graphics."

Did any software ever use math co-processors?  The guy I work with told me his college PC had one, but he said nothing used it.

Tell him I said he's an idiot. Tons of software used it. Especially astronomy ephemerides calculations. Lots of science stuff, simulations, CAD tools, and a even a few games like Falcon 4.0 or Quake. Earlier games rarely (if ever) used it.