Need help with the backstory of how the game was made

I'm making a game that's meant to be made during 1987-1990, and I have a few things that I want to get correct. First of all, would it be possible for someone to make a game engine for computer games and put it into a floppy disk, and if not, would it at least be possible for someone to make some tools to help them with coding a game?

 

Yes, that was possible and occasionally done.

 

Okay, thanks so much for your help!