20 Aug
2022
20 Aug
'22
7:06 p.m.
On Sat, 20 Aug 2022, Chuck Guzis via cctalk wrote:
field use, so it was acceptable to record tracks at
various offsets to
get a good idea of how far from the radial ideal the customer's drives
were. I'm a bit surprised with the call for finding alignment disks,
that this hasn't been done in the hobbyist world. After all, what most
folks rehabilitating drives are interested in is radial alignment. I
doubt that many know how to adjust azimuth.
The Dysan Digital Diagnostic Diskette included track(s) where SECTORS were
recorded progressively offset!
I can visualize, and am impressed with, how you offset tracks for
alignment diskettes, but I'm having difficulty imagining the Dysan
mechanism. Large intersector gaps, and a separate pass for writing each sector?
One sector would be aligned, one sector a little too far in, next sector a
little too far out, next sector further in, next sector further out, next
sector further in, next sector further out, next sector further in, next
sector further out,
How far you could read, and whether your reads were mostly even numbered
or odd numbered, told you which direction the radial alignment was off, and a
slight approximation of how much.
It was hilarious here on the list decades ago, when there was a
participant who claimed that the copy-protection bypassing cloning program
that he had could duplicate alignment diskettes! ('course he also claimed
that FORTRAN was based on Valtrep, that he had a copy of OS/2 for PDP-11,
and that a 1980s machine that he had worked on was the FIRST machine that
ever did email)
--
Grumpy Ol' Fred cisin(a)xenosoft.com