I remember the 8" floppies in use in 1980 at my new job. The 8" floppy was invented by IBM in the late 1960's per Wikipedia.
Yes, late 1960s for inclusion in the IBM mainframe hardware, and the original application for the 8 inch floppy drive was to load the microcode into the control storage of the IBM-370 computer. The earlier IBM-360 microcode was read-only memory in the form of ribbons or tapes, with holes cut to make either a zero or one bit. The microcode is used to decode and execute each machine instruction in the operating system and user's application program. Using a floppy enabled the IBM-370 to quickly update microcode when updates were necessary, It also allowed an alternate microcode set to emulate earlier IBM computer instruction sets while customers migrated to native 370 code. Much later, it became a general-purpose mass storage device.
When I first operated a 370, I thought, how neat it would be to have that device in a home computer. In the late 70's, I built an 8080 machine from scratch. The two 8 inch floppy drives set me back over $500 each, not including the controller hardware, power supply, enclosure, etc.