Curious about vgmusic creation

[ORL13]

How exactly was older vg music created, like on sega, nes and snes? For instance, when Koji Kondo sat down to record the music for super mario world what did he use and how did he record it? Did he just use a synth? I've always been curious about that and thought maybe someone here might know...

Also does anybody know any good programs or methods for making classic video game sounding music? I'm pretty much a n00b at this and would love to know where to start