One thing that comes to mind, what IF the drive is so quiet that after it
spins up you think it's spun down? <g>

The spin down could be a result of the drives uControllers shutting it down
for power savings.

I was able to acquire a copy of the ATA Interface Spec.  You can read (err,
skim through it). It's a few hundred pages, so you'll definetely have to
refer to the TOC.  Specifically, the ones about the ATA Command Set.  These
commands can be sent via the lower bits (D0-D7, 8-bits) instead of using all
16 lines.  Anyways, here's the link to the spec.

ftp://fission.dt.wdc.com/pub/standards/x3t13/project/

The one you want is d1321r1a.pdf or d1321r1a.zip  The ZIP file contains the
spec in DOC form.

Tim Hamel

In a message dated 6/22/99 1:24:41 PM Pacific Daylight Time, lktron@YAHOO.COM
writes:

> Hello,
>  Thanks to everybody for your helpful answers.
>
>  I have the PC power connector (the 12v/5v +grounds)
>  plugged into the hard drive. Nothing connected to the
>  IDE plug. Then when I turn on the power, the motor
>  spins up and after a short run stops.
>
>  When I ground the RESET pin (pins 1 and 2 ) the drive
>  spins and then stops again. I have one drive, a
>  Quantum ST64A011 which will spin continously, as long
>  as the pins are shorted. But other drives I have do
>  not. I tried a Seagate laptop hard drive, and applied
>  +5v to the motor pin and logic pin, it wiggles a bit
>  and then stops.
>
>  Strange?
>
>  Perhaps as Tim Hamel suggests, I need to send CCB or
>  CBC commands to the drive, but then waht is the
>  digital equivalent and which pins is the signal sent
>  to?
>
>
>  In any case, I want to use a hard drive because I am
>  doing an optics experiment and the hard drives by
>  their design are very highly balanced, whereas if I
>  were to get a servo, I would need to balance
>  everything
>  and it would be ...
>