Naked backplanes….
….make life so much easier than the cramped, heavily shielded enclosures PDP’s had in their first lives. The thought of inserting and especially removing cards without donating copious amounts of blood is almost incomprehensible to this veteran.
Come across “one?” Try PDP-11/20 (operating an instrument at a mountaintop observatory), multiple -11/34s, commanding, receiving data from, and analyzing those data from instruments on a spacecraft, an -11/40 used by another project, that borrowed me for some grunt work, and a schizophrenic -11/70 that ran IAS during the day and Unix at night. Probably others this geezer can’t recall right now.