The creation of
ENIAC caused the creation of many worlds including:
ENIAC's younger sibling, UNIVAC, is insanely jealous that it didn't get to create any worlds, and is currently plotting a terrible vengeance.
PC and Mac spend nearly every offscreen moment trying to keep the crazy old man in check.
The following universes are related by having alternate versions of each other's
Cyber Space.
All digital worlds coexist, but use incompatible operating systems.
They all exist simultaniously but never interact with oneanother because they are incombatible with each other. A character from Tron can't travel to a Digimon world because the Digimon operating system can't run the Tron character's program. Attempting to join the digital worlds via the internet creates The Web, as seen in
Reboot, which breaks down the programs of every digital character not native to The Web, preventing the digital worlds from interacting online.
Jossed in the case of
DMFA, as that is set in Furcadia...