On 9/27/2022 8:50 PM, The Natural Philosopher wrote:
> On 27/09/2022 19:52, Tim Streater wrote:
>> Few years ago I replaced four or five external hard drives here with SSDs.
>> These have sat around but now I've stirred my stumps to erase them prior to
>> disposal. They'll get random data written everywhere and then zeroes. They are
>> 7200rpm, various sizes of 1TB, 2TB, and 3TB.
>>
>> Question is, is there any value left in them? With SSDs of similar size going
>> for £100 or less, is it worth the faff of trying to sell them?
>>
> Probably not. Old hard drives are a failure waiting to happen.
There is no way to predict what will happen to a disk.
I have one disk here, ST3500418AS Made in Thailand,
that has more than 50,000 hours on it. It's in great shape.
Other disks from the same epoch, only last 6,000 hours
before presenting symptoms.
Sometimes you get a good one.
With FDB motors, there's no reason they have to die.
The ones with ball bearing motors, there is friction
and the assurance they will gradually wear out.
The FDB motor is frictionless, once up to speed.
If the FDB motors have retention on both ends of the
rotor (not all do), then it can last a long time.
Only loss of lubricant, dooms an FDB. The motor seals
are key.
The disk in question, does not spin down or park either.
It is always ready to field a request. It remains flying.
I have other disks, which are supposed to work that way,
but the bastards put parking in the firmware. Then it's slow
to answer if it has gone to sleep.
Very few drives, outright die on you now. They're more
likely to be showing Reallocated Raw non-zero, and make
you nervous about their future.
Try to keep the drives in the same orientation they have
been used over their service life. I had one drive, in
a refurb PC, which seemed to have suffered some high-fly
errors. And I could no longer trust it. The drives are
rated for operation in six compass point orientations,
but personally, I would not take a drive that had
been operating right side up (the 50,000 hour one),
and flip it upside-down for fun.
As for the Helium drives, I suspect they could last
a lot longer, as there is no breather hole and no
exchange of atmosphere with the room air. The helium drives
are only "guaranteed" to have helium in them for five years.
The critical seal is via an adhesive, where the helium
can only escape through the depth of the sealing surface.
There is a cover for mechanical rigidity, which does not
contain the helium, and the adhesive is what keeps the
gas in. Two covers. Helium starts at 6TB or 8TB or so,
and go up to 18TB to 20TB now. I have zero helium drives.
Room conditions determine the service life of drives. I
think a dry room for the air breathing drives, is a lot
better for them. While the hepafilter disc is designed
to make it hard for moisture to enter, it's just a matter
of time and atmospheric pressure cycles. The hepafilter disc
is on the inside of the drive, on the cover, and just
under the breather hole. It helps ensure the inside stays
clean.
Charging a small sum for each drive, is a way of saying
to the purchaser that you think there is still life in them.
Use your usual test procedure for hard drives (acceptance test),
before selling a drive on. I would have no qualms about
selling that 50,000 hour drive onwards, because all tests
pass and Reallocated is still zero. The HDTune benchmark curve
doesn't have spikes in it (from Reallocations you cannot see).
The 6,000 hour drive, with the non-zero Reallocated, I'd stick
that in the dust bin. It still works, but if I won't use it
myself (does not pass Acceptance Test), then I would not expect
a buyer to put up with "trash".
One of the drives I got from the computer store recently
(WD Black 1TB), was completely dead on arrival. Seemed to
have a motor power issue, and would not attempt to spin.
Just because a product is "new", does not mean a thing. That's
the very first drive I've purchased, to have a problem like that.
Naturally, it did not pass the Acceptance Test.
From a performance perspective, many of the old drives are
too slow for any practical purpose, but you will discover
purchasers are desperate for a "deal". I bet I could sell
my Western Digital 4GB drive with the 5MB/sec transfer
rate. It's still perfectly functional. Low service hours.
Perfect for an antique PC for a museum project. Would be
no good for booting a bloated OS.
The power-on hours, is a field in the SMART table.
http://www.hdtune.com/files/hdtune_255.exe # for a win user
Paul