Atlas was one of the first supercomputers and pioneered technologies that we are not even aware of. History of IT is very fascinating and these simulators allow modern users to experience how these machines worked under the hood.
https://www.icsa.inf.ed.ac.uk/research/groups/hase/models/atlas
I discovered these simulation tools while learning about old innovations that pushed the world forward. These things are now abstracted away while developers today work on things such as LLMs without even learning how their computers are doing what they do.