🚀 go-pugleaf

In article <7795@nigel.udel.EDU> jacobs@chocolate.it.udel.edu (michael jacobs) writes:
>In article <JACOBS.90Jan9093359@cmos.cs.utah.edu> jacobs@cs.utah.edu (Steven R. Jacobs) writes:
>=>In article <7715@nigel.udel.EDU> jacobs@chocolate.it.udel.edu (michael jacobs) writes:
>=>>In article <3226@ucrmath.UCR.EDU> lulu@ucrmath.UUCP (david lu) writes:
>=>>=>I just tried to format some 1.2 Meg, high density disks in my
>=>>=>360K drive (as 360K), and I got the following error message:
>=>>=>
>=>>=>	Invalid media or Track 0 bad - disk unusable
>=>>
>=>>Having just had this problem, I asked around and it seems that High Density
>=>>disks and Double Density disks (used for 360k) do have physical differences.
>=>>
>=> On the high density disks, the
>=>oxide is a different material which requires a stronger magnetic
>=>field to record information.  The heads in many 360K drives are
>=>not designed to produce a strong enough magnetic field to record
>=>data on the high density floppies.
>
> I'd call that a physical difference.  It has to do with what the floppy
> is made of, not on just what the floppy drive is doing.

Sure, it is a physical difference, but the disk manufactures
don't go to any extra trouble to make the high density disks unusable
in 360K drives.  If there were no physical (i.e. materials) differences
between the two types of disks, everyone would use ordinary disks
in the high density drives (this is possible, but not recommended).
--
Steve Jacobs  ({bellcore,hplabs,uunet}!utah-cs!jacobs, jacobs@cs.utah.edu)