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#6820 - 12/18/09 08:40 AM TTP SMART failure with new iMac
dondenny Offline


Registered: 12/05/09
Loc: Kalamazoo, MI
Using TechTool Pro v5.0.6, I ran a SMART check of the internal hard disk (NVidia 500GB) in my recently purchased iMac (3.06 GHz Intel). The Attribute Graph indicated all aspects passed except the "temperature changes" which failed at the farthest end of the spectrum. How concerned should I be?
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#6821 - 12/18/09 11:15 AM Re: TTP SMART failure with new iMac [Re: dondenny]
Virtual1 Offline


Registered: 08/04/09
Loc: Iowa
Many SMART attributes are all-or-nothing shots, or are "one defect fails". Sounds like the drive saw itself overheat once, and that was unacceptable to ever happen. (overheating can cause permanent damage, rendering it forever unreliable)

I generally consider any drive with a failing SMART status to be in need of immediate replacement. The checks I do on my drives go far beyond SMART, and in many cases I've caught a drive that was showing early signs of problems long in advance of SMART status toggling. (several of them toggled to FAIL while I was rescuing my data off to a replacement drive!) So although SMART can be an early warning, it's not as much advance notice as I'd like to see, and more often than not drives fail catastrophically before SMART toggles, so it's of limited use. But when it toggles, you should respect the warning you're being given.

If you send your mac in for warranty service, they will SWAP the hard drive, and you will have to specifically request (and pay for) data recovery to the new drive. So either make sure you get that, or that you have a backup yourself, if there's anything on the drive you need. (you said it was new tho so maybe not?)
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#6847 - 12/19/09 12:20 PM Re: TTP SMART failure with new iMac [Re: Virtual1]
dondenny Offline


Registered: 12/05/09
Loc: Kalamazoo, MI
Thanks, Virtual for your thoughts and experience. It's good to know you and others from the late/lamented MFI forums are still available when I'm in a jam.

Since posting my query, I spoke with a tech at Apple Support, who suggested (a) that I check my Disk Utility for its current report re: SMART and (b) access the Apple Hardware Test on my system install disk and see if it reported any problem. Disk Utility indicated that SMART status was "verified" and AHT in an extended check reported "no trouble found." There was no indication that AHT included the temperature of the internal hard drive in its battery of tests. I also reviewed an extended forum discussion from earlier this year at the MicroMat TTP 5.0 user forum regarding SMART failure reports due to "temperature changes" (attribute 190), which suggested the problem is not uncommon (especially in Seagate hard drives, although my drive is an Nvidia), and the accuracy, meaning, and implications of some SMART reports are uncertain. Apparently not all applications check all SMART factors. MicroMat doubted if Disk Utility checks temperature changes, for instance. I wasn't able to find any relevant info on any of these matters through Nvidia's web site.

In the MM forum discussion there were some references to an application (widget?) which can report the current internal (drive? cpu?) temperature. Are you familiar with this and its utility in my case?

BTW, the Apple tech suggested I had little to worry about due to drive failure as a result of persistent high temperatures because (a) the system would react with shutting down and a warning before meltdown; and (b) the one year warranty on my iMac would replace the defective drive in such an event.

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#6848 - 12/19/09 01:19 PM Re: TTP SMART failure with new iMac [Re: dondenny]
artie505 Online


Registered: 08/04/09
> In the MM forum discussion there were some references to an application (widget?) which can report the current internal (drive? cpu?) temperature. Are you familiar with this and its utility in my case?

Temperature Monitor may be what you're looking for; there's an app as well as a widget.
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#6850 - 12/19/09 05:45 PM Re: TTP SMART failure with new iMac [Re: dondenny]
joemikeb Online
Moderator

Registered: 08/04/09
Loc: Fort Worth, Texas
Not long after I got my new iMac TTP had reported an initially unknown S.M.A.R.T. value as out of range, but DU said the drive passed S.M.A.R.T. With the help of Google I was able to find the unknown S.M.A.R.T. value was heat related. I contacted Western Digital and they said no third party utility was capable of accurately interpreting their S.M.A.R.T. readings. A few weeks after that the drive failed completely and had to be replaced under warranty. The day before the failure TTP was still reporting and out of range S.M.A.R.T. value and DU was still insisting that S.M.A.R.T. was "verified".

Personally I will take TTP's word from now on. The problem is convincing Apple and/or the drive manufacturer to accept it as well.
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#6858 - 12/20/09 08:19 AM Re: TTP SMART failure with new iMac [Re: joemikeb]
MicroMatTech3 Offline


Registered: 08/04/09
Disk Utility does not report S.M.A.R.T. attribute 190.

One of our customers reported that Seagate will not accept reports of a S.M.A.R.T. failure unless it comes from Seagate’s own SeaTools software. The software is not available in a version that runs under Mac OS X. For Intel-based models, there is a version that runs under DOS, and should work, but neither our customer nor the beta administrator for TechTool Pro was able to boot from the disc that can be made from the disk image Seagate provides and run SeaTools.

The relevant thread in our forums, with links to several pages at the Seagate site:

Criteria for SMART Pass/Fail?

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MicroMat Inc
Makers of TechTool

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#6860 - 12/20/09 11:35 AM Re: TTP SMART failure with new iMac [Re: MicroMatTech3]
Virtual1 Offline


Registered: 08/04/09
Loc: Iowa
In the past, every time I've been asked to provide a validation code from a HD testing software that would not run under mac, they had an option that said you were using a mac, and that seemed to remove the need for the code.

ALSO you may not be aware that Disk Utility does SMART testing for all internal drives as of 10.5. (and 4?) Open Disk Utility and the HD name on the left will appear in RED and if you select it it will tell you the drive is failing. So you don't need TTP or anything else to test the overall status of SMART on mac.

The reason this works is that even for the "custom"/proprietary SMART attributes that you don't necessarily even know what they mean, the drive also provides an upper limit number for each attribute. If the current value exceeds the limit, for ANY ONE attribute, the overall SMART status is FAIL. Some attributes start at 0 and immediately are set to 1 or 255 if the event occurs even once. (like overheat) You may not know why but you will know it's bad.

The reason some of them want a validation code is because they will NOT be testing your drive when you send it in, and the VC tells them that yes you really did run the test and yes it really did fail. The VC is tied to the drive's serial number so you can't use the same VC for another drive, you have to run the tool on the drive to get it. So they're doing it to prevent "insurance fraud" on their warranty. Too many (adjective) people were waiting until a month or two before their drive went out of warranty and then doing a claim to get a new (refurb).
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#6864 - 12/20/09 12:56 PM Re: TTP SMART failure with new iMac [Re: artie505]
dondenny Offline


Registered: 12/05/09
Loc: Kalamazoo, MI
Thanks for the link, Artie. Temperature Monitor seems to be a nifty (and free) app that monitors and reports several internal temperatures in addition to that of the hard disk. The vendor's web site FAQs makes the following interesting observations:

"S.M.A.R.T. is the abbreviation of Self Monitoring, Analysis, and Reporting Technology . It is an industry standard introduced in 1992 to react earlier on hard disk failures. A hard disk supporting the S.M.A.R.T. standard monitors itself with its own micro processor and allows the operating system to request readouts that indicate whether operational parameters have changed in such a way that the hard disk might become defective in the near future. In this case the hard disk can be replaced before any data is lost.

Some hard disk manufacturers allow the computer to request additional detail information, e.g. the current operating temperature of the disk. However, this feature is not an official part of the S.M.A.R.T. standards. Not every disk supporting S.M.A.R.T. is capable of providing temperature readings. Either the data is not measured at all, or the hard disk manufacturer did not publish how the data can be read out from the disk controller." I had not understood earlier that temperature parameters are not a routine part of the SMART report in all cases.

Temperature Monitor FAQs also discusses the question of what value for a given computer is WNL and the app provides the user with a table which will identify that value if Apple has specified a range. If no range is listed, Apple has not published one. There is no SMART temp normal range listed in the table. The FAQ then states, "Note that all up-to-date Macintosh models automatically shut down or enter sleep mode if one of the readings exceeds a critical limit. For this reason it is impossible that your computer can be damaged in an overtemperature condition." This is essentially what Apple tech support told me, too. In other words, the data is apparently only academic, so don't worry. But if this is the case, then how does TTP/MM know when a hard disk temp is too high and needs to reports it as a SMART failure? Perhaps MMT3 can provide some insight here.




_________________________
"For every complex problem, there is a simple, easy to understand, incorrect answer."

Albert Szent-Gyorgyi

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#6867 - 12/20/09 02:03 PM Re: TTP SMART failure with new iMac [Re: Virtual1]
MicroMatTech3 Offline


Registered: 08/04/09
I can only tell you that as joemikeb reported above, TechTool Pro may report a S.M.A.R.T. failure while Disk Utility passes the drive, because Disk Utility ignores attribute 190 and some other attributes that are vendor-specfic. It looks only at the lower-numbered attrribtes, the ones that all manufacturers agree upon the meaning of.
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MicroMat Inc
Makers of TechTool

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#6868 - 12/20/09 02:07 PM Re: TTP SMART failure with new iMac [Re: dondenny]
MicroMatTech3 Offline


Registered: 08/04/09
Reporting S.M.A.R.T. failures does not require interpreting anything. Whenever the current value for an attribute falls below the threshold for that attribute, a failure is reported. It is up to the maker of the drive mechanism to ensure that the reported failure provides meaningful information to the user of the drive.
_________________________
MicroMat Inc
Makers of TechTool

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#6882 - 12/20/09 09:19 PM Re: TTP SMART failure with new iMac [Re: MicroMatTech3]
dondenny Offline


Registered: 12/05/09
Loc: Kalamazoo, MI
MMT3 . . .

I don't understand. The provider of Temperature Monitor says in his FAQ notes that Apple has not defined a normal range for hard drive temperatures, so how does TTP determine when a drive has failed or passed a SMART test? If the TM folks are wrong and there is a defined acceptable temp range and TTP reflects that in its assessment, what is that range? Assuming TM measures drive temperature accurately, it would help me to be able to monitor the temperature pattern against the acceptable range. I am admittedly very limited in these technical matters and if I'm missing something, I hope you'll go over it again s l o w l y.

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#6884 - 12/21/09 04:22 AM Re: TTP SMART failure with new iMac [Re: dondenny]
MicroMatTech3 Offline


Registered: 08/04/09
TechTool Pro does not read temperatures as such, by using the temperature probe in the drive. It reads the S.M.A.R.T. data that the drive itself records in its own firmware. On some drives, there is a S.M.A.R.T. attribute that refers to the drive’s temperature.

The program compares the threshold for a particular S.M.A.R.T. attribute, which the drive mechanism maker put in the firmware, to the current value for that attribute, which the drive itself wrote during use. If the current value for a particular attribute is below the threshold for that attribute, a failure is reported when TechTool Pro examines the S.M.A.R.T. data. That is the way all S.M.A.R.T. reporting works. The only differences among programs are which attributes are being read, and how the results are being reported (text report, dialog box, graph, for example).
_________________________
MicroMat Inc
Makers of TechTool

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#6887 - 12/21/09 05:50 AM Re: TTP SMART failure with new iMac [Re: MicroMatTech3]
dondenny Offline


Registered: 12/05/09
Loc: Kalamazoo, MI
Thank you. Your explanation makes the issue much clearer.
_________________________
"For every complex problem, there is a simple, easy to understand, incorrect answer."

Albert Szent-Gyorgyi

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#6893 - 12/21/09 09:43 AM Re: TTP SMART failure with new iMac [Re: dondenny]
joemikeb Online
Moderator

Registered: 08/04/09
Loc: Fort Worth, Texas
This is is relatively old news now, but this white paper from Google labs is still the most extensive and comprehensive study of disk drive failure available. Among other things, it analyzes the value of S.M.A.R.T. as a predictor of impending drive failure and concludes that S.M.A.R.T. is much better at telling you when a drive has failed than predicting when it will fail. They fault the drive manufacturers choice of tolerance settings for S.M.A.R.T.'s poor predictive results.

Their conclusion is the best predictor of impending drive failure is a surface scan such as TTP or Drive Genius can perform. Unfortunately a full surface scan takes a long time to perform.

FWIW, one feature of TTP's S.M.A.R.T. report I like is its reporting of the individual parameters and not just the summary verified/failed of Disk Utility and most other utilities that rely on the same results as DU does.
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#6896 - 12/21/09 10:08 AM Re: TTP SMART failure with new iMac [Re: dondenny]
MicroMatTech3 Offline


Registered: 08/04/09
You are welcome.

I suggest that you use Temperature Monitor or iStat Menus to get an idea of what normal temperatures are for your drive. Make a few notes comparing the reported temperatures to the ambient temperature in the room.
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MicroMat Inc
Makers of TechTool

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