The most recent issue of MagPi has quite a section on retro computing - emulation of old systems, etc. Got me thinking about my first intro to Unix back in the early 90's on DecStation 5000 with CDE interface. Earlier this week, I downloaded the source, compiled the CDE system (2 or
3 hours on a Pi3) and with the help of the associated guide and a couple of web searches, I have it running.
Talk about nostalgia!