27 Jun
2014
27 Jun
'14
7:58 a.m.
On Jun 27, 2014, at 07:45 , Al Kossow <aek at bitsavers.org> wrote:
On 6/26/14 6:49 PM, Mark J. Blair wrote:
That might be a good approach for reading packs with damaged servo bursts, but the
application I had in mind was writing servo bursts to a degaussed platter.
It seems to me that by adding a positional
transducer to the head and a suitable servo system, it should thus be possible to position
the head arbitrarily, with resolution limited by the transducer.
If you're going to throw hardware at it, put a DSP in the read channel and positioner
and derive the track position on
the fly based on the recovered data with coarse positioning based on the gross amplitude
of the entire track. The method should also work for Apple Widget disk data
recovery, where most of the drive mechanisms have failed
due to the glue failing on the glass graticule used for coarse servo positioning.
I didn't know that the Widget drives used closed loop servo. Interesting!
--
Mark J. Blair, NF6X <nf6x at nf6x.net>
http://www.nf6x.net/