Re: HD floppies in a DD drive.

[rubywand@aol.com (RUBYWAND)]

In article <4o6tdo$l2r@tribune.concentric.net>, Erick & Janet Wagner
<wagnere@cris.com> writes:

>
>I agree with Joe.  This question has come up on Genie beefore and it 
>was mentioned that the DD and HD hardware in the disk drives put out
>different signal strengths when recording on magnetic media.  Therefore
>it's possible that too strong a signal or too weak a signal is used when
>writing data back to the disk.
>
>

     The 'grey area' seems to be cheapo HD's that appear to work okay as
DD's. I did some magnetic deflection tests comparing a cheapo HD surface
vs. a DD surface. (As William Krantz, Jr. observed earlier, the DD does
show a slightly browner tint than the HD.)  Each surface was magnetized
just prior to deflection measurement. The DD surface showed notably higher
magnetization as indicated by more than twice the deflection produced by
the HD surface.

     Granted, the test does not prove that some HD's won't work fine on
Apple IIgs 800K drives. The HD surface tested was from a batch of cheapo
HD's that, with very few exceptions, have worked. So far, failures have
been no worse than with DD's.

     However, it is clear that any drive optimized for the tested DD
surface cannot be optimized for the tested HD surface-- there is too much
difference in surface characteristics.

     Keeping a few IIgs HD's around for periodic checking seems
reasonable. It also seems like a pretty good idea to copy the HD stuff to
DD's and stick with DD's from now on.


Rubywand