I was updating my Linux Process Snapper /proc sampling/profiling tool [1] and ended up curious about when did this concept (examining process state via reading

I was updating my Linux Process Snapper /proc sampling/profiling tool [1] and ended up curious about when did this concept (examining process state via reading special files) first show up. Back in 1984 already, pretty wild! And, according to Wikipedia, it was first meant to replace the usage of ptrace() syscall [2]. [1] https://tanelpoder.com/psnapper/ https://tanelpoder.com/psnapper/ [2] https://en.wikipedia.org/wiki/Procfs#UNIX_8th_Edition https://en.wikipedia.org/wiki/Procfs#UNIX_8th_Edition