Paul wrote:
Jason wrote:
When I booted the machine today, one of the disk drives
didn't show up in the configuration. No errors in logs
that I could find. Disk Management didn't list it, but it
was marked "disabled" in the Device Manager. I enabled it
and a message popped up informing me that this usually
was caused by an error condition with the drive. I ran
all the tests and it passed. I've never seen this before.
Was it just a random Windows event or should I begin
shopping for a new drive? It's a spinning drive, not SSD,
and is four years old.


I've never heard of that before.

Do you suppose it wasn't "ready" when the
BIOS handed off control to the OS boot process ?

The BIOS is supposed to wait up to 35 seconds for
a hard drive to finish spinning up. Some older
Hitachi (IBM?) drives came perilously close
to that limit, at around 28 seconds or so,
when in the prime of their lives.

Smaller drives use aggressive startup current
(2 amps), so they can be ready in 5 seconds.
A larger capacity drive may use a lower motor
current like maybe 1.5 amps and take a little
longer to spin up. It would appear boot
drives are trying to start faster (a 500GB
disk being a good boot drive, a 4TB less so).

*******

There is one kind of failure event, where the
processor on the hard drive goes crazy and
hangs. SATA drives have no RESET wire and when
you press RESET button on the PC, it doesn't
actually put the SATA drive in a known-good state.

To clear a crazy SATA drive, requires power cycling
the device (remove +5V/+12V from the interface).
Soft power off is good enough (shutdown) for this
purpose. If the crazy drive was the C: drive, then
you might be forced to use the power switch on the
back of the PC, to recover it.

And the root cause for events like that, is the
SATA power cable chain has too much loading, and
the SATA voltage has dropped to around 11VDC or so.
I had this happen on the machine I'm typing on, and
the drive goes into a loop spinning down and spinning
up again. And the processor can go crazy when the
power is of poor quality.

*But*, if a drive goes crazy, it stops responding entirely,
so no amount of Device Manager poking will make it
appear. And that means this isn't a match for
your symptoms.

*******

If it passes testing, I don't know what to tell you,
except to make a backup and continue to observe it
for signs of trouble. For example, you could watch
the IDE LED on the front of the computer case,
for clues as to what is going on.


What I have experienced and Paul hinted at, if a drive tests okay but
fails to be recognized intermittently it typically is a power issue.

1) the power connection flaky...check to another available connection
may solve the issue.

2) If not, new power supply is where I'd go.

--
Take care,

Jonathan
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