[renewedrebecca]

For the C64 at least, the cool thing is the absolute lack of abstractions. The entire memory map is known. The entire Kernal is documented. The hardware, totally explained. You can actually know everything there is to know about the whole machine. Totally different than modern computing / coding.

[gnufx]

Good point, that we've mostly gone backwards in that respect. Sites did used to have source for all the software and hack on it, and detailed docs on the hardware that wasn't self-built.