The good old days!
Ah! Takes me back. My Heath H8's separate H17 floppy box used single-sided, single-density, hard-sectored 5.25" disks. You could get 90K on 'em once formatted for CP/M. HDOS left you a little over 100K, I think. And the wonderful KA-CHUNK! KA-CHUNK! as the Wangco drive heads made contact with the media.