Question about 360k disk usage...

[vwestlife]

Over the years I've seen plenty of warnings about this, but little, if any, proof of the problem actually happening.

I've written to 360K disks all the time in 1.2MB drives and rarely had any problems reading them again in 360K drives. The few times I did were with the old full-height drive in my IBM 5150 PC. I think (but have not been able to confirm) that the later half-height 360K drives used narrower heads to reduce the compatibility problem with reading data that had been written by 1.2MB drives.

Besides, these days with 5¼" floppy disks you're more likely to have problems with degradation of the media, fungus growing on the disk, dirty drive heads, drive mechanisms that need to be lubricated, etc. than any problems you can specifically blame on a 1.2MB drive writing to a 360K disk.

[Stone]

Over the years I've seen plenty of warnings about this, but little, if any, proof of the problem actually happening....

I've written to 360K disks all the time in 1.2MB drives and rarely had any problems reading them again in 360K drives.

I have.

It doesn't happen with every drive.

Some 360K drives are able to read disks made on 1.2M drives and some aren't.

Some 1.2M drives are able to write 360K disks that 360K drives are able to read reliably. I had a 1.2M drive in a 286 that I used all through the 1990s to write 360K disks that were used on 360K drives in hundreds of computers without any problems whatsoever. I'd give almost anything if I still were able to use that particular drive.

I've also had 1.2M drives that wrote 360K disks that no 360K drive could read.

It all depends on the drives themselves, both types. Some are and some aren't, on both ends.

[Unknown_K]

Isn't the problem that the disk tracks are half the width on a 1.2mb drive compared to the 360K drive (which is also why you can take a 360K disk and format it to 800K on a 1.2MB drive)? I assume the heads are different sizes.

[Xacalite]

Isn't the problem that the disk tracks are half the width on a 1.2mb drive compared to the 360K drive (which is also why you can take a 360K disk and format it to 800K on a 1.2MB drive)? I assume the heads are different sizes.

Exactly.
A 1.2MB drive writes narrow tracks.
A 360KB drive is designed to read wide tracks, so if the track is narrow, it's read along with the noise from adjacent area.
Degaussing the media before writing it in a 1.2MB drive helps, as it zeroes the adjacent area noise.