There’s something slightly creepy about this video from Apple – a demo of the Apple Lisa from 1983. But it shows how, even then, there was a need for a resource scheduling tool.
The Lisa came with 7 software programs including one called LisaProject. It was the first graphical project management software. It had some pretty amazing features for the time, including the ability for users to interactively draw their project in the form of a PERT chart and also output a Gantt chart. There was a resource chart too, where you could see resource availability.