Re: 50 MB in the '80s?
Same story - as a newbie I was keen to follow the rulebook and that said you didn't call an engineer until you had done your own first-line diagnostic work to identify the exact problem. I loaded an EDS200 pack, wouldn't come on line, so I tried the same pack on another drive unit to see whether the fault followed. In fact just to be sure I tried it on several other drive units.
Of course the defective disk pack had broken all of them and I made the mistake of writing up the engineer call with "description of defect: can hear tinkling noise from drive units." My resulting nickname "Tinkle" took a long time to live down.