Let me elaborate on generations for you.
First generation.
Magnavox Odyssey • Pong • Coleco Telstar
Second generation.
Fairchild Channel F • Atari 2600 • Interton VC 4000 • Odyssey² • Intellivision • Arcadia 2001 • Atari 5200 • ColecoVision • Vectrex • SG-1000
Third generation.
NES • Master System • Atari 7800
Forth generation.
TurboGrafx-16 • Sega Mega Drive/Genesis • Neo Geo • Super Nintendo
Fifth generation.
3DO • Amiga CD32 • Jaguar • Saturn • PlayStation • Nintendo 64 • Virtual Boy
Sixth generation.
Dreamcast • PlayStation 2 • GameCube • Xbox
Seventh generation.
Xbox 360 • PlayStation 3 • Wii
First generation would actually be four bit gaming. When you reverse the math backwards. I cannot say for certain if the Odyssey was a four bit machine. Probably quite likely when you compare it to the eight bit NES. I think the bit reference is a throw back to a time when each next generation was twice as powerful as the previous one. I am not sure todays machines are actually 256 bit or not. The industry no long seems to use the terminology, and further more exactly where would those bits be applied.







