Originally Posted by tore

I don't know about Steam as I haven't bought any really old titles there, but if you buy old titles on Good Old Games, they come with a DOSBox emulator (emulates a DOS environment). So there's no porting needed there at least. It would make sense for the Steam guys to do the same.

You can too if you want to download and play old games. It's easy If you need help, I can write you a quick guide.