@Bobbelieu I had to use similar devices back in the day. They collected lab data from medical labs.
The hard drives were basically open to the air like that, the whole room was refrigerated, and had to be dust-free. If a bit of hair or dust or something got in the case and onto one of the platens, and hit the write head, it was bad.
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@AskTheDevil I worked at a materials research company in Silicon Valley back in the 80's and I had an instrument in the lab that had a PDP-11 computer with two (count 'em 2) 40MB hard drives. Two separate drawers held 4 platters each. One drawer held the operation software for the instrument and analysis files and the other drawer held the drive we stored spectra data on. Good times....
@Bobbelieu Better than tape reels and punch cards.