clabretro did an interesting video on the hardware of a 1997 PowerPC RS/6000 machine: https://www.youtube.com/watch?v=r8IFtnD5oOM
At the time also posted on HN: https://news.ycombinator.com/item?id=31485616
It provides a few details on the software stack, particularly also the set of compat-APIs for porting Linux applications.