Why do good floppy disks go bad?

[Paul Koning]

> On Apr 6, 2016, at 8:55 PM, Geoff Oltmans <oltmansg at gmail.com> wrote:
> 
> On a related note... What causes an old mfm / roll drive to die if the heads aren't touching the surface except in the landing zone?
> 
> I have read that it's not impossible for the "pigment" to lose its coercivity over time.

I would like to hear an explanation of the physics behind that claim.  Off hand, I don't believe it.

A likely cause of drive failure is contamination.  That could come from inadequate seals (or seals that degrade over time).  It could also be from contaminants released by components of the drive itself, if their chemistry is not quite right.  It doesn't take much to cause a head crash.

	paul