> On Feb 27, 2023, at 10:21 AM, Mike Katz via cctalk <cctalk@classiccmp.org> 
> wrote:
> 
> the drive would see half the new data and half the old data.

I think that explaining it this way can easily lead to an incorrect inference 
on the part of an arbitrary hypothetical neophyte that what is going on in the 
drive in such a case is that the head can equally well read either the old data 
or the new data but the controller can’t distinguish which is which, or might 
return old data, or might return new data, or might indiscriminately return 
some old data and some new.

What the drive reads in such a case is noise, because the wider head picks up a 
superposition of the old (wide) 48tpi track data AND the new (narrow) 96tpi 
track data, simultaneously.


ok
bear.

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