19 Feb
2019
19 Feb
'19
5:10 p.m.
On Feb 19, 2019, at 8:00 PM, Fred Cisin via cctalk
<cctalk at classiccmp.org> wrote:
On Tue, 19 Feb 2019, Fred Cisin via cctalk wrote:
Rather than flux transitions, flux levels would seem even better. If the flux levels are
sliced and reduced to square waves, you've lost a bunch of information that could have
helped recover marginal data.
I' reminded of the Bordynuik tape reading machine that uses an MR head. Capturing
analog flux levels at, say, 10x the nominal flux change density means all the rest is
simply digital signal processing. That can be done in real time if you must, but much
more easily in post processing using whatever tools and languages you like.
paul
As I see it, flux transition hardware COULD be
all that is needed for hardware. Emulation of FDC could be done in software with flux
transition hardware.
That should read flux transition plus appropriate control signals for the drive. Seeking
tracks, turn on the drives R/W circuitry, etc.
Flux transition ITSELF is just making sense out of the pulses on the track.