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From: Simon on 4 Sep 2008 23:44
Arno Wagner <me(a)privacy.net> wrote
> Simon <192900(a)spam.com> wrote
>> Arno Wagner <me(a)privacy.net> wrote
>>> Franc Zabkar <fzabkar(a)iinternode.on.net> wrote

>>>> My MPF3204AT Fujitsu 20GB HDD's Power On Time Count just
>>>> triggered a SMART warning after dropping below the threshold of 20.

>>>> The raw value is currently 43763894 seconds, ie 12156 hours.

>>>> OTOH my 120GB Seagate drive is currently at ...

>>>> Power On Hours Count 9 0 99 99 0000000005DDh (1501)

>>>> ... so its expected life appears to be somewhere between 150,100 and 75,050 hours.

>>>> Are these numbers realistic, ie has hard disc reliability really improved that much? I don't think so.

>>> This is not reliability. This is component life under operation.
>>> It has improved significantly due to better lubrication
>>> material as has non-operating component life. Here also because
>>> of the move to ceramic capacitors, that basically live forever,

>>> while electrolytes die after 3-5 years or so, depending on temperature and quality.

>> Fantasy.

> Read a datasheet.

Doesnt say a damned thing about that mindlessly silly claim.

And have fun explaining how come the power supplys which have many more
much bigger electros in them dont even have that 3-5 years in their datasheet.

>>> But, no, I would say the 7.5/15 years are probably still
>>> longer than you can realistically expect. Typical component
>>> life for industrial electronics is still around 5 years.

>> Like hell it is.

> Again, read a datasheet.

Again, have fun explaining the power supply data sheets say nothing like that
and that fact that decent power supplys last a lot longer than that anyway.

>>> I guess this is just so that the range is large enough.
>>> It should be an "old age" attribute anyways, not a "pre-fail."

>>>> The Fujitsu datasheet ...

>>>> http://www2.fcpa.fujitsu.com/sp_support/ext/desktop/datasheets/mpf3xxxat-datasheet.pdf

>>>> ... specifies the number of start/stop cycles as 40,000.

>>>> A log of SMART reports shows the following:

>>>> Start/Stop Count 4 16 98 98 000000000578h EC
>>>> Start/Stop Count 4 16 97 97 00000000057Dh EC

>>>> This suggests that each point represents about 468 starts, and a
>>>> loss of 84 points represents 39,340 start/stop cycles which roughly
>>>> tallies with the spec.

>>> Well, you should be prepared for your drive to become unreliable in the not to far future.

>> Mindlessly silly.

> And again, read a datasheet.

And again, the datasheet says nothing like that on the drive becoming unreliable.

>>> But these values are not hard. If you have backup, you can continue
>>> to use them and may even get some more years of reliable operation.

>> Gets sillier by the minute.

> And get a clue about device live statistics.

It you that needs to do that.

>>> And, realistically, that is not too different from what a new deive gives you.

>> Even sillier.

> You have no clue.

You in spades.

> On a guess I would say one of the usual clueless bigmouths,
> hiding behind a new name, because nobody listens anymore.

Guess again. Those who reply must have done, fool.


From: chrisv on 5 Sep 2008 09:30
Arno Wagner wrote:

>>> while electrolytes die after 3-5 years or so, depending on temperature and quality.
>
>> Fantasy.
>
>Read a datasheet.

Umm... Arno, many (most?) of us have first-hand experience with
electronics lasting MUCH longer than that. And of they all, in
general, use electrolytic caps.

In my experience, 10+ years of lifetime is routine and, really,
expected from an electronic device.

From: chrisv on 5 Sep 2008 10:43
chrisv wrote:

>In my experience, 10+ years of lifetime is routine and, really,
>expected from an electronic device.

If you want, you can come-over and I'll fire-up my circa 1985 Amiga
A1000 for you. (But I conceed that the HD is newer - circa 1989 8).

Alas, my (also) circa 1985 Sony KV25XBR died within the last year,
after over two decades of heavy use...

From: Arno Wagner on 5 Sep 2008 13:43
Previously chrisv <chrisv(a)nospam.invalid> wrote:
> Arno Wagner wrote:

>>>> while electrolytes die after 3-5 years or so, depending on temperature and quality.
>>
>>> Fantasy.
>>
>>Read a datasheet.

> Umm... Arno, many (most?) of us have first-hand experience with
> electronics lasting MUCH longer than that. And of they all, in
> general, use electrolytic caps.

> In my experience, 10+ years of lifetime is routine and, really,
> expected from an electronic device.

Remember the "capacitor plague"? There the lifetime was reduced
from about 5 years average to 1-3 years average on typical operating
conditions. Where you hit? I was several times, the first one after
2 years operating time of the mainboard in question.

Then there is the thing, that the life time is not the time
after which it fails, just the time where the probability per
time unit starts to increase significantly. Of course some units
will life much longer. I have several HDDs older than 5 years
that work fine. Also the failure mode can vary greatly.
For example, if you have a good quality PSU, probably even a total
capacity loss of an input filter electrolythe will not matter much.
With a bad PSU it may lead to significant problems.

Also, we are talking about a HDD here. It may run hot. Derate
lifetime typically at a factor of 2 per 10C. A well cooled PCB
may be at 25C. An uncooled at 55C or more. I did not only say
"3-5 years" , I added "depending on temperature and
capacitor quality". I should also have added "design quality".

What I claimed for capacitors was that circuit designers
tend to target a 5 year lifetime at _expected_ contitions.
Most people here will cool HDDs well. That are not the
expected conditions anymore. But remember all the people
that lost Maxtors early and it turned out they were not
cooled well? Sometimes after 1-2 years?

So predictiong lifetimes is difficult. Possibly I should
have been far more specific. I apologize for that. But
the numbers are not fantasy at all.

Here is a real number from a very high quality low-ESR
Electrolythe capacitor (Rubycon ZLH, 7mm hight): 1000h at 105C.
Lifetime here means capacity within +/-25% of original, leakage
still within datasheed value and dissipation (related to internal
resistance) <= 200% of datasheet value.

Arno
From: Arno Wagner on 5 Sep 2008 13:51
Previously chrisv <chrisv(a)nospam.invalid> wrote:
> chrisv wrote:

>>In my experience, 10+ years of lifetime is routine and, really,
>>expected from an electronic device.

> If you want, you can come-over and I'll fire-up my circa 1985 Amiga
> A1000 for you. (But I conceed that the HD is newer - circa 1989 8).

No need, I have an Atari ST that works fine. But this
is not "lifetime". This is "shelf live unoperational". And that
Atari ST has some replaced electrolythes, because I had to fix them
to solve a stability problem.

> Alas, my (also) circa 1985 Sony KV25XBR died within the last year,
> after over two decades of heavy use...

Good design then. My (expensive) Sony Vaio died after 2 years of
light use. The cause was chipset overheating due to inadequate
cooling.

It just boild down to several things:

- Treat electronics well and they will live longer
- It is statistics. Lifetime is just when failures start to get more
likely. Some things die withing a year, some keep 20 years. Can
still be 5 years lifetime.
- Not all failures kill a thing. Some do not matter at all.
- Personal experience is not a global predictor.

Arno

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