Re: Good source for "new" 5.25 and 3.5 inch floppy disks?

[winston19842005 <bjjlyates@bellsouth.net>]

On 9/22/07 8:05 AM, in article
46f504fc$0$16116$9b4e6d93@newsspool1.arcor-online.net, "Linards Ticmanis"
<ticmanis@gmx.de> wrote:

> winston19842005 wrote:
> 
>> The Wikipedia entry didn't seem to mention coercivity at all... And I know
>> for sure that was a difference in 5.25", but 3.5" is the question.
> 
> Well, Steven is right in saying that the only reason to adjust write
> current is to deal with a different coercivity. I'm not a physicist, but
> AFAIK there's simply no other reason why you would do it.

Found some info:
http://books.google.com/books?id=E1p2FDL7P5QC&pg=RA1-PA660&lpg=RA1-PA660&dq=
coercivity+on+floppy+disks&source=web&ots=M0tgBda_cz&sig=ZI_6EB1BzRzC-H85gva
9-6t5ic0#PRA1-PA660,M1

Gee, what a link - don't know what is trimmable. Here is a tinyurl:
http://tinyurl.com/yqwm85


This is a book preview that just happens to have what we want.
Go to pages 659-660...

To sum it up, you are right - there are differences (I'm tired of typing
that "C" word).

There is a table on p 659.
                                   5.25"                         3.5"
                                   DD          HD        DD         HD
Coercivity (oersteds)              300        600       600        720
Thickness of media (microns)       100         50        70         40

Just guessing, but see that the coercivity difference between the 3.5" DD
and HD is 120, vs. 5.25"'s 300 difference. And the thickness difference is
less too...

Considering the differences are less, it seems plausible to assume that
there is a better chance of data loss in the situation of 5.25" HD disks
written in an LD drive (which has been definitely what I've seen) than 3.5"
HD disks written in either an LD drive or an HD drive with the HD hole
covered on the disk (which is again what I've seen).

I guess "whatever works for you" or "play it safe and don't do it".

The book referenced is "Upgrading and Repairing PCs by Scott Mueller"...

Anybody want to update the Wiki entry on this, who has experience?