Why won't a compiled program run on any computer?

Answer 1

First, because it depends on libraries that may or may not be present on other computers. If you compile a Windows .exe program, for instance, it's going to be trying to make calls to Windows APIs like WIN32 and/or WPF. So if you run it on Mac OS X or Linux, it's going to be looking for the Windows stuff that it needs to run and it's going to be totally lost.

WINE is an open-source project that basically acts as a translator for Windows apps on other platforms. It's used in stuff like Crossover Games, a Mac app that lets you run certain Windows games on a Mac. It's not perfect, though, and even if you can get a Windows game or app to run using WINE it might run into quirks, like video cutscenes not playing.

Second, the problem of different processor architectures. This is why you can't use WINE on a PlayStation 3 or an older Mac with a PowerPC processor, even if they're running an OS (like Linux or Mac OS X) that can theoretically support WINE. It's because when a program's compiled, it's only compiled to run on one particular processor architecture, like Intel/AMD or PowerPC or the ARM chips in mobile handhelds. Put it on anything else, and it can't run. The Mac world is split between two different processor architectures (Intel and PowerPC), so they deal with this stuff pretty frequently, although not as much as in 2006 when the first Intel Macs appeared. Ask them about "universal binaries" sometime.

It's also why my Android phone chokes on certain Super Nintendo games. Emulators aren't just a translator like WINE, they have to literally simulate the whole hardware architecture of the platform they're emulating. So my modern high-powered smartphone slows down when running an 18-year-old game for a 20-year-old console, because it's trying to pretend to be every circuit inside that console while it's doing it. But it has to in order to run them.