Actually HD temp has proven to be of little consequence to harddrive lifespan. Google conducted a test a couple years back and found next to no correlation to HD temp and drive failure. Google did this over 5 years by recording every failure they had and took many variables into account to come up with probably one of the most comprehensive real world hd reliability tests.

Statistics can be misleading. The fact that most drives didn't fail because they were too hot does not put aside the fact that many of them failed because they were too hot. So, it is a good practice to keep the disks at a relatively low temperature. Good practices should be followed regardless of a particular outcome. -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org

It's only a good practice if it's based in empirical fact, not merely intuition.

It is an empirical fact that disks *do fail* because they are too hot. Mostly, the electronics fails, some integrated circuit gets burned. Please don't isolate one of my statements from the whole of my post. The central point was: "Statistics can be misleading. The fact that most drives didn't fail because they were too hot does not put aside the fact that many of them failed because they were too hot." We could discuss this forever. *In practice* I am sure you understood what I meant. -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org

On Wednesday June 17 2009, Miguel Medalha wrote:

...

...

It's only a good practice if it's based in empirical fact, not merely intuition.

Somewhat off-topic, it could certainly be said that intuition, too, is an empirical fact.

Absolutely, positively not. Randall Schulz -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org

On Wednesday June 17 2009, Miguel Medalha wrote:

...

...

Somewhat off-topic, it could certainly be said that intuition, too, is an empirical fact.

Absolutely, positively not.

For many people, real intuition -- I am not talking about "guesses" here -- definitely is an empirical fact.

The brain has two hemispheres, you know.

Having two hemispheres is entirely beside the point. Both contribute distinct cognitive abilities and both contribute to intuition. Both are even necessary for science, but that's all irrelevant to what intuition is and that category to which it's suggestions belong.

Subjectivity is -- fortunately -- also a fact of life.

The subjective is just that: Existing in the mind of a cognitive agent. It may reflect objective reality, but it need not and often does not. Intuition is the result of unconscious mental processes. That it occurs is a fact and everyone has it, but what a person's intuition suggests is categorically not in the realm of fact. It _always_ requires empirical validation. Randall Schulz -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org

That, too, is excessively dependent on semantics. If you believe that "most don't" is consistent with "many do," fine. It strikes me as dubious.

Not dubious at all. Heat IS a factor on HD drive failure. SOME will fail due to excessive heat. I prefer that NONE of the ones in my possession does fail due to the heat factor -- which is SOMEWHAT under my control -- and hence I keep them within reasonable temperature limits. That's all. -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org

David C. Rankin wrote:

http://www.3111skyline.com/download/screenshots/driveTempFailure- ProbabilityDensity.jpg

You were complaining about your mail reader breaking URLs into half. One reason is when people forget to format URLs correctly in emails: http://www.3111skyline.com/download/screenshots/driveTempFailure-Probability... The carrot brackets are there for a reason. This is the reason! Cheers, Dave Oh, and the graph of course also shows that decreasing temperature below about 37 results in an increased failure rate. Which does not agree exactly, or even vaguely, with what you said. -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org

* Boyd Stephen Smith Jr. [06-29-09 11:54]:

I've used "", "<$URL>", and simply "$URL" and none of them give consistently good results. The second is broken just as often as the other two, and some clients stick the trailing '>' in the URL.

Yes, instead of just clicking on the url to select for past or klipper action, you have to grap the start and finish inside the "<>". This is a *broken* _semi_-standard. -- Patrick Shanahan Plainfield, Indiana, USA HOG # US1244711 http://wahoo.no-ip.org Photo Album: http://wahoo.no-ip.org/gallery2 Registered Linux User #207535 @ http://counter.li.org -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org

Boyd Stephen Smith Jr. wrote:

In <4A48C2E6.5090907@mrc-lmb.cam.ac.uk>, Dave Howorth wrote:

...

David C. Rankin wrote:

...

http://www.3111skyline.com/download/screenshots/driveTempFailure- ProbabilityDensity.jpg You were complaining about your mail reader breaking URLs into half. One reason is when people forget to format URLs correctly in emails:

How is this:

...

<http://www.3111skyline.com/download/screenshots/driveTempFailure-Probabil ityDensity.jpg>

Any more "correct" that just writing the URL out? Specifically, what IETF RFC, W3C recommendation, or IEC, ISO, or IEEE standard specifies this?

RFC 3986, though it was in the predecessor RFC2396 since at least 1998. http://www.faqs.org/rfcs/rfc3986.html See "Appendix C. Delimiting a URI in Context" and especially "In such cases, it is important to be able to delimit the URI from the rest of the text, and in particular from punctuation marks that might be mistaken for part of the URI. In practice, URIs are delimited in a variety of ways, but usually within double-quotes "http://example.com/", angle brackets http://example.com/, or just by using whitespace: http://example.com/ These wrappers do not form part of the URI. In some cases, extra whitespace (spaces, line-breaks, tabs, etc.) may have to be added to break a long URI across lines. The whitespace should be ignored when the URI is extracted. No whitespace should be introduced after a hyphen ("-") character. Because some typesetters and printers may (erroneously) introduce a hyphen at the end of line when breaking it, the interpreter of a URI containing a line break immediately after a hyphen should ignore all whitespace around the line break and should be aware that the hyphen may or may not actually be part of the URI. Using <> angle brackets around each URI is especially recommended as a delimiting style for a reference that contains embedded whitespace"

I've used "", "<$URL>", and simply "$URL" and none of them give consistently good results. The second is broken just as often as the other two, and some clients stick the trailing '>' in the URL.

As you can see, it is the interpreting MUA that is broken, not the format. The rules for interpretation are pretty clear, I think. I understand M$ out-of-luck is particularly bad. Carlos wrote:

Alpine, for one, knows that it should not wrap a http://someplace URL. And hitting [enter] or click on it more or less works.

Yup, Thunderbird too. Cheers, Dave -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org

Boyd Stephen Smith Jr. wrote:

I'll continue following this RFC by using whitespace. Specifically ASCII code point 0x20 a.k.a <SP>. If your MUA breaks the URL, I'll just tell you to fix your MUA. :P

Since I now know that you know, I simply won't repair broken URLs in mail from you ;P Hopefully, that won't ever stop me helping you. Cheers, Dave -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org

On Tue, 30 Jun 2009, Dave Howorth wrote:-

Boyd Stephen Smith Jr. wrote:

...

Any more "correct" that just writing the URL out? Specifically, what IETF RFC, W3C recommendation, or IEC, ISO, or IEEE standard specifies this?

RFC 3986, though it was in the predecessor RFC2396 since at least 1998.

It was also in RFC1738[0], from December 1994: APPENDIX: Recommendations for URLs in Context URIs, including URLs, are intended to be transmitted through protocols which provide a context for their interpretation. In some cases, it will be necessary to distinguish URLs from other possible data structures in a syntactic structure. In this case, is recommended that URLs be preceeded with a prefix consisting of the characters "URL:". For example, this prefix may be used to distinguish URLs from other kinds of URIs. In addition, there are many occasions when URLs are included in other kinds of text; examples include electronic mail, USENET news messages, or printed on paper. In such cases, it is convenient to have a separate syntactic wrapper that delimits the URL and separates it from the rest of the text, and in particular from punctuation marks that might be mistaken for part of the URL. For this purpose, is recommended that angle brackets ("<" and ">"), along with the prefix "URL:", be used to delimit the boundaries of the URL. This wrapper does not form part of the URL and should not be used in contexts in which delimiters are already specified. Interestingly, RFC2396 removed the recommendation to add URL: to identify a URL. [0] URL:http://www.faqs.org/rfcs/rfc1738.html Regards, David Bolt -- Team Acorn: http://www.distributed.net/ OGR-NG @ ~100Mnodes RC5-72 @ ~1Mkeys/s openSUSE 10.3 32b | openSUSE 11.0 32b | | openSUSE 10.3 64b | openSUSE 11.0 64b | openSUSE 11.1 64b | RISC OS 3.6 | RISC OS 3.11 | openSUSE 11.1 PPC | TOS 4.02 -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org

Miguel Medalha wrote:

...

Actually HD temp has proven to be of little consequence to harddrive lifespan. Google conducted a test a couple years back and found next to no correlation to HD temp and drive failure. Google did this over 5 years by recording every failure they had and took many variables into account to come up with probably one of the most comprehensive real world hd reliability tests.

Not "of little consequence". People tend to quickly jump conclusions but in fact the data needs interpretation.

<snipping much angst> Hi kids! For the physics of the problem, see http://en.wikipedia.org/wiki/Arrhenius_plot "From the Google data, calculate the activation energy for temperature-induced hard drive failure" ;-) -- Tony Alfrey tonyalfrey@earthlink.net "I'd Rather Be Sailing" -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org

Dave Howorth wrote:

Tony Alfrey wrote:

...

Miguel Medalha wrote:

...

...

Actually HD temp has proven to be of little consequence to harddrive lifespan. Google conducted a test a couple years back and found next to no correlation to HD temp and drive failure. Google did this over 5 years by recording every failure they had and took many variables into account to come up with probably one of the most comprehensive real world hd reliability tests.

Not "of little consequence". People tend to quickly jump conclusions but in fact the data needs interpretation.

<snipping much angst>

Hi kids! For the physics of the problem, see http://en.wikipedia.org/wiki/Arrhenius_plot

"From the Google data, calculate the activation energy for temperature-induced hard drive failure"

Interesting idea. Do you have a link to some evidence that disk failures are governed by an Arrhenius relation?

Grain boundaries are physical phenomena rather than chemical. I thought the current evidence pointed to them behaving like a glass.

The Arrhenius relation is often applied to stochastic processes with some ill-defined temperature-related causality. Your grain boundary example is good. While there is a specific amount of energy required for a portion of the boundary to make a "break", and while the average thermal energy at room temperature may be well below that energy, there is still a finite probability that the break occurs because the Boltzmann relation provides some tiny fraction of the whole ensemble of 'boundary segments' at a temperature equal to the 'break temperature'. It's like a problem I was once given in Statistical Mechanics: a) Calculate the energy required for a penny sitting on a table to jump up and flip over. b) Calculate the probability that the penny will do this spontaneously at room temperature. The Arrhenius relation is a nice fall-back when the failure rate looks logarithmic. -- Tony Alfrey tonyalfrey@earthlink.net "I'd Rather Be Sailing" -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org

Dave Howorth wrote:

Tony Alfrey wrote:

...

...

Tony Alfrey wrote:

...

Miguel Medalha wrote:

...

...

Actually HD temp has proven to be of little consequence to harddrive lifespan. Google conducted a test a couple years back and found next to no correlation to HD temp and drive failure. Google did this over 5 years by recording every failure they had and took many variables into account to come up with probably one of the most comprehensive real world hd reliability tests.

Not "of little consequence". People tend to quickly jump conclusions but in fact the data needs interpretation.

<snipping much angst>

Hi kids! For the physics of the problem, see http://en.wikipedia.org/wiki/Arrhenius_plot

"From the Google data, calculate the activation energy for temperature-induced hard drive failure" Interesting idea. Do you have a link to some evidence that disk failures are governed by an Arrhenius relation?

Grain boundaries are physical phenomena rather than chemical. I thought the current evidence pointed to them behaving like a glass. The Arrhenius relation is often applied to stochastic processes with some ill-defined temperature-related causality. Your grain boundary example is good. While there is a specific amount of energy required for a portion of the boundary to make a "break", and while the average

Dave Howorth wrote: thermal energy at room temperature may be well below that energy, there is still a finite probability that the break occurs because the Boltzmann relation provides some tiny fraction of the whole ensemble of 'boundary segments' at a temperature equal to the 'break temperature'. It's like a problem I was once given in Statistical Mechanics: a) Calculate the energy required for a penny sitting on a table to jump up and flip over. b) Calculate the probability that the penny will do this spontaneously at room temperature.

The Arrhenius relation is a nice fall-back when the failure rate looks logarithmic.

So no actual evidence then :-P

I'm not sure what "evidence" you would feel comfortable with. If I were to take the Google data and fit it to an Arrhenius plot and calculate an activation energy that was roughly consistent with what one might expect for one of the many possible temperature-related failures in a disk drive, would that be appropriate? This is, by the way, how one does science. If you'd like, I'll do the calc and submit the paper as a letter to Jour. of Phys. C. If the paper gets published, does that then make it "evidence"? If someone else publishes the paper, is that then better evidence than *my* paper? Do you reject the idea that an Arrhenius relationship is *not* appropriate? Do *you* have an alternate proposal? Do you, perhaps, not understand the qualitative analysis I presented above? <sigh> -- Tony Alfrey tonyalfrey@earthlink.net "I'd Rather Be Sailing" -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org

Dave Howorth wrote: <snip>

So far what you've said is pure speculation.

<snip> Yes. You're right. I think I'll go have lunch now. -- Tony Alfrey tonyalfrey@earthlink.net "I'd Rather Be Sailing" -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org

Adam Tauno Williams wrote:

...

FWIW, I didn't see any data in the Google paper itself that supported the relationship you suggest - perhaps you'd point it out

All of which misses the point. Perhaps the correlation [except in the extreme] of heat to drive failure is low; but the COST of a 80mm fan is also low. The chances of getting in an automobile accident are [individually] very low each time I get into my car - but I always but on my seat belt because the inconvenience [cost] of using the seat belt is very low. If a $4 fan makes a very minor improvement in drive failure probability - then it is $4 well spent.

My original assumption about disk failure was that they would fail statistically (versus temperature) like any other electronic component. But this assumption is suspect. While the Google data are messy (we don't know anything about the drive populations and if they were purchased in blocks at one time from one manufacturer or another) it is hard not to conclude from the Google data that there is an optimal operating temperature for a drive (about 45 C). If your $4 fan keeps the drive temp at 30 C, the Google data indicates that it may cut drive lifetime in half, roughly equivalent to the failure rate at 50 C. So it certainly forces *me* to want to reexamine my assumptions about drives. -- Tony Alfrey tonyalfrey@earthlink.net "I'd Rather Be Sailing" -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org