Then there was sectors, which was common to have 8, though again you could with better quality discs (quality did get better ahead of the standards) you could go with 9 sectors and higher - https://www-user.tu-chemnitz.de/~heha/basteln/PC/usbfloppy/f....
Of course, you could think of it as over-clocking - was no guarantee you get that extra capacity, and the early days - it was really luck, but like most things, quality improves and such avenues of formatting became more accessible.
In the ST era, the control of that motor was directly under the control of the operating system. For an 80 track disk, the movement required to step between tracks was a certain known amount.
If you formatted the disk with the tracks spaced closer together, by altering the stepper movement during that process, you would 'magically' get more space.
No, it was under control of a stepper motor driver circuit located directly on a Floppy drive pcb. This driver in turn received instructions from a dedicated Floppy drive controller (WD1771 and compatibles).
> For an 80 track disk, the movement required to step between tracks was a certain known amount.
"certain known amount" being one step per track
>If you formatted the disk with the tracks spaced closer together, by altering the stepper movement during that process, you would 'magically' get more space.
Above is incorrect.
Its impossible to move HEAD stepper motor between tracks. Floppy drive has a STEP (/STEP) and DIRECTION (/DIR) pins. All you are able to do is pick direction and step one track at a time. Step distance is Fixed. The whole point of using a stepper motor is you dont have to worry about head tracking/alignment.
The only personal computer Floppy drives with flexible head positioning all used voice coil head actuator - Floptical, LS-120/240, Zip drives etc.
You could format extra tracks, if you felt lucky. Usually you could get away with couple extra. I never did this with any files I valued.
I recall the default format was 9 sectors, 80 tracks, 2 sides with 512 bytes per sector = 720KB, and you could push up to sometimes 82/83 tracks and maybe 10 or 11 sectors to get more out of a diskette.
Actually, I think my ST originally came with a single-sided floppy drive and had to be upgraded.
Sad thing was, due to the early single sided models, many games would limit to 720k so as to not limit there market. That saw games that would happily fit upon a single double sided disc, cast upon two floppies forcing switching. So that small batch of single sided initial release systems, really did have a legacy impact that lasted for years and did it no favours.
The standard 720KB 3.5' floppy disk as used by the Atari ST used 80 tracks of 9 sectors.
With these tools you could format with, say 11 sectors instead of 9 and boost capacity to 880KB (I think the Amiga was doing that as standard).
[1] https://en.wikipedia.org/wiki/List_of_floppy_disk_formats
Edit: another unrelated practice was buying up cheap(er) single-density disks, which were distinguished by the lack of a marker hole opposite the r/o protection slider, and used only one side of the medium for data. By drilling it out, one could trick the drives into using both sides, which usually worked out just fine. Mentioned here [1]
Spinwrite still exists, though in the early days/versions it was the golden tool for tuning up a system and could make huge differences. Like double your drive speed and more in some instances, but talking late 80's early 90's here when interleaving was thing and mid 90's 1:1 became the norm and made it moot. https://www.grc.com/Spinrite.htm
I have heard about how formatting a floppy involved placing the tracks and how modern hard drives have “hard sectors”, but for some reason, it’s not “computing.”