Re: [vcf-midatlantic] Drive repairs, was Hard drive art

On Sun, Apr 21, 2019 at 05:04:25PM -0400, Jason Perkins via vcf-midatlantic wrote:

Some drives (Apple Widget, Plus Hardcard / Quantum) had a fine position sensor on the head arm. The Lisa disk uses this during a low level format.

Found picture of the drives online. Looks like they used an optical position sensor similar to how my RK05's work. This was probably the last gasp of that method before the track density got too high for it to work. Are you saying the Widget only uses it to format? How does it determine head position during normal operation? For my RK05 its always uses the optical sensor for positioning the heads.