>So, what’s a PC compatible? No modern PC will run the DOS that the original PC ran. Now define "modern PC". Oh boy, we've hit a dependency loop. PC compatibl

>So, what’s a PC compatible? No modern PC will run the DOS that the original PC ran. Now define "modern PC". Oh boy, we've hit a dependency loop. PC compatible means your software runs without error on MS-DOS. That's the definition I've used for 3 decades, and it should not change due to bloggers' retrospective. Of course, 100% IBM PC compatible is a level above this, when your software works exactly as if it were running inside an IBM PC.