In the early 1990's. I used 3.5" FD's in my Spectral Dynamics 385 spectrum analyzer. It was a modified TEAC drive that would get about 1Mb in a special SD format. When I would baseline a new press, I would store point by point data on these disks for later retrieval and review. I would buy them several hundred at a time. I still have them filed away. There are probably thousands of them. But, I still have the SD 385, and I may want to look at them some day.

It probably does not even work. It has been stored for at least ten years. I've still got the disks though.