Single-use computers
I have two stories.
My first job out of college in the late 1970s was for a small magazine publisher (73/Kilobaud) in western New Hampshire. They had a PR1ME 300 mini, used both to manage subscriptions and to handle merchandise orders (TRS-80 games on cassettes!) The system was in an attic above a garage, with no air conditioning, so windows were open during the summer. Not only did it get hot and humid, but bugs and other debris came in the windows. The disk packs, in particular, did not like this. The publisher, a noted cheapskate, of course did not buy a service contract for the system. After a year of this I found a better job with DEC.
In my early days there, we had someone come in from Schlumberger and give a talk about what they did with our computers. I vividly remember hearing him explain how they would lower an LSI-11 (PDP-11/03) down a borehole with some sensors attached, and a cable leading up the hole to a van with recording equipment. An "event" would occur in the borehole, the van would jump up off the ground using springs, and record lots of data until the poor LSI-11 was vaporized.