On Aug 27, 9:37 am, demp...@actrix.gen.nz (David Empson) wrote: > This is risky, because the magnetic properties are different for double > density and high density, and a HD disk written as if it was DD won't be > very reliable. Actually for 3.5" media the difference is slight. Many manufacturers actually used the same formulation for DD and HD media, as a cost reduction method.