aek at bitsavers.org
Tue Jan 20 11:47:31 CST 2015
On 1/19/15 10:43 AM, Tom Gardner wrote:
> FWIW, microstepping goes back to at least the CDC SMD of the mid-70s and
> even some stepper motor drives were microstepped. So there is no question
> the XT2190 can do it.
Obviously, though with the limited documentation it would take some reverse
engineering of the Maxtor servo system to do it. There is no way provided to
do it from the 34 pin edge connector that I can see. Know anyone that has
any Maxtor schematics squirreled away?
Someone on Eric's board just asked if ESDI was backwards compatible to ST412
like it incorrectly states on Wikipedia, which got me to re-read the ESDI
spec http://bitsavers.org/pdf/micropolis/ESDI_spec_X3.170-90.pdf and the
good news is there were commands added to microposition the heads there.
Doesn't help with the immediate problem, thought. This is all an interesting
rathole, but I'm down too many others right now.
I looked at an early ESDI spec in the CDC/discs directory, and there was
a step-mode defined which was backwards compatbile, but I have no idea if
any drives actually implemented it, since you still have separate clock and
data on the 20-pin connnector so what's the point?
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