my Data General Nova 4/X, disk woes continue

[Tom Jennings]

On Mon, 25 Apr 2005, jim stephens wrote:

> The other thing you mentioned but didn't comment on the condition of is
> the grating and the optical sensor for said.  are they clean?  also, on
> the drive's we had, of the western dynex and microdata variety, you
> could physically feel the drive or the voice coil and feel it vibrating
> when there was a servo problem, in most cases, or hear a difference
> in the seeks as it failed.

It's pretty clean; I have not touched it. I can RTFM on cleaning
it, but the drive was very clean to begin with.

If there's a servo problem it's pretty subtle. I'm talking 10%
error rate (or whatever) not 100%. Mostly it reports in higher
cylinder numbers. This isn't a go/nogo problem -- I wish!

I will however stare at it and look for bulk odd behavior first.

I'm sure there's an error voltage off the servo I can look at, as
well as other nice closed-loop thingies. The documentation is
excellent, it has huge waveform diagrams and state diagrams (flow
charts).