Discussion at the time: https://news.ycombinator.com/item?id=45840321
And more developments and analysis since:
An initial analysis of the discovered Unix V4 tape
https://news.ycombinator.com/item?id=46367744
Unix v4 (1973) – Live Terminal
https://news.ycombinator.com/item?id=46468283
Fixing a Buffer Overflow in Unix v4 Like It's 1973