Modern floppy disk question...

[Jim Leonard]

Eric Smith wrote:
> Track density is definitely NOT the problem.  The track density of a
> 720K 3.5" floppy is so low compared to the flux density along a track that
> the former is essentially irrelevant.  Track density is 135.5 TPI, but
> flux density ranges from 4885.8 FTPI on track 0 side 0 to 8323.0 FTPI
> on track 79 of side 1.  (Double those FTPI numbers for 1440K disks.)
> 
> The increases to the FTPI were accompanied by changes to the oxide
> formulation to have higher coercivity.  Most 720K 3.5" disks from the
> early 1980s and 1440K 3.5" disks from the late 1980s are fine, though
> there was some bad stuff back then as well.  But today it seems that
> none of it is good.  It's definitely the quality of newly manufactured
> media at fault, since the older media still works well.

I stand corrected :-)  To which I can only conjecture:  Today there is less of 
a demand for 3.5" media, so maybe the lack of competition/demand results in an 
inferior product due to cost cutting?
-- 
Jim Leonard (trixter at oldskool.org)                    http://www.oldskool.org/
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