On 22 Mar 2010 at 17:54, Fred Cisin wrote:
In addition to all that, . . .
The coercivity (sorta like magnetic sensitivity) is WRONG.
"720K" diskettes are 600 Oersted.
"1.4M" diskettes are about 750 Oersted.
It IS close (unlike 360K (300 Oersted) v 1.2M (600 Oersted)), and it
WILL work (unlike 360K v 1.2M), but it will NOT be as reliable as
using the correct diskette.
It's much more than that. Coating thickness (DS2D uses a thicker
coating than DSHD). Particle size (DSHD uses a smaller particle).
Loading (DS2D loads the binder more heavily).
If you've got one of each type, slide the shutter over and look at a
bright light through the cookie. Usually, you can see quite clearly
through DSHD media, but DS2D is almost always opaque.
Gotta be something to that...
I recall that some were even formatting DS2D media as DSED in the bad
old PS/2 days. Numerous claims of it working--but for only a short
time. DSED uses a barium ferrite formulation rather than an iron
oxide.
--Chuck