Format issue

[wjy8969]

When I use ARDUINO NANO (328p oldbootloader) to format a 5.25-inch floppy disk, tracks 1 to 29 cannot be read or written normally, with errors "Sector header not found" and "No sync marks found". Please help me.Thanks to you all!!

[dhansel]

Just to clarify: does reading/writing tracks 30-79 work properly and only tracks 1-29 don't work or have you not yet tested the other tracks? ArduinoFDC does nothing special for tracks 1-29, so if the others work then it is more likely that your disk drive or disks have a problem.

Also, you say "When I use [ArduinoFDC] to format a ... disk" - does that mean that tracks 1-29 do work if you use a disk that was already formatted by some other means?

[wjy8969]

I used a floppy that already format. Before format that floppy by arduino, I use low-level disk monitor read tracks to test them. And they are work well. Just to add, I am using a DD floppy disk in the HD drive.

[dhansel]

As far as I know, writing a DD disk in a HD drive is generally not recommended. Something about the finer HD drive write head not always being able to "flip" the larger-grain magnetic particles in the DD disk. I'm not 100% sure whether this is true though.
Does writing a HD disk in your HD drive work?

[montyleib]

I'll second that, David, although I would word it as gospel. Any DD disk written by a HD drive will be difficult/impossible to read on a DD drive due to the track width of the heads. A fresh or magnetically bulk erased DD disk written by a HD drive will have 1/4 track worth of different noise on either side of the data (may or may not read), while a used DD disk written by a DD drive, then written to by a HD drive will have 1/4 track of old data on either side, meaning a DD drive will 'see' a half-track of both old and new data, and will not read.

[wjy8969]

HD disks also have the above problem, after formatting, some tracks change from working normally to reporting an error "Sector header not found"

[montyleib]

That comes from alignment issues, below spec write current, or physical damage.