iOS came from NeXT when they brought Jobs back to Apple and NeXT OS was a derivative of Unix with a better GUI. So yes, they all do this. Microsoft learned everything they know about multitasking / multiuser / networked OS kernals from IBM. They had a joint venture to develop OS/2 and MS pulled out, then launched NT from their IP they got from OS/2. IBM had the largest global multiuser systems in the world and top scientists for both software and hardware. Microsoft had DOS, a single user, single CPU, 640K limited, character-based OS. IBM made Microsoft successful - first with DOS, then Windows and NT (Windows' core was first DOS, then switched to NT with the XP version, their 1st real multitasking version of Win).