I’m old enough to know what this is. I’m so old that I actually used these. They were the first hard disks we were confronted with. We called them “Phoenix” (but I don’t remember their original brand name). A single 14” platter in a plastic case which was shoved horizontally into the drive. When you heard a screeching noise, the disk was kaputt.

The disk had a capacity of 5MB. That’s not a typo: it’s about 1% of the size of the boot partition of your Apple Watch, I guess, but that’s all we had.