On 09 Apr 2021 12:36:37 +0100 (BST), Theo declaimed the following:
Don't even attempt to read an old Amiga floppy unless you have a drive that can stream an entire raw track.
That's how the Amiga packed 880kB on a "720kB" floppy. It removed most of the inter-sector timing markers, would read for just over one revolution of the disk, and then decode the track in RAM to find sectors, which were then collected/reordered to the front of the buffer. On a write, it would just start writing the bit-stream for a full track. It did NOT use a Start-of-Track marker, and would write at whatever position the disk happened to be at.
Made it easy, however, for an Amiga to read other floppy formats -- CrossDOS handled common IBM floppies. It was a bit more difficult to manage some of the Apple floppies as they were constant bit-width on track (more sectors on the outside rim than near the hub, where common floppies with fixed sector counts had narrow bits near the hub, and spread out bits near the rim).