Some software programs can etermine the temperature of the hard drive. E.g. HWMonitor:

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I say that there must be a thermometer inside the HDD and the data (via SMART) is passed as regular info to the soft which wants that info .

My colleague say that no, there's no thermometer inside the HDD. (i.e. the software guesses the heat based on the drive's RPM.)

How do programs determine the temperature of the HDD?

  • 17
    Your colleague is completely clueless and foolish.
    – barlop
    Apr 28 '13 at 22:44
  • @barlop What happens then when there's no temperature monitors in those HDDs? superuser.com/questions/588878/…
    – Pacerier
    Jun 5 '15 at 6:12
  • @Pacerier yrs ago people either didn't know the temp at all or wud stick a temperature sensor pad on the/a device.That was done more4the CPU temp(that's more important than hard drive temp),some people put a probe on the heatsink(or in-drilling in) . People put pads on hard drives to measure their temp too.Tho@some point over a decade ago, motherboards started monitoring/reporting CPU temp,n hard drives started reporting their temp.And at some point infra red thermometers came out and it's possible to point them(like a gun) at whatever one can see eg at hard drives,and measure the temp of them
    – barlop
    Jun 5 '15 at 10:03

The hard drive has a temperature sensor (or multiple temperature sensors - they might be used for internal control, self-test etc...) inside, and this data is passed through SMART (in fact, this is a standardized SMART parameter).

  • 5
    Aye. OP could have found by just reading http://en.wikipedia.org/wiki/S.M.A.R.T., scrolling to parameter 190 ans searchinf for the word temperature. (E.g. open page, <kbd>Control</kbd>-<kbd>F</kbd>, temperature <kbd>Enter</kbd>).
    – Hennes
    Apr 28 '13 at 20:00
  • 2
    @Hennes I assumed it relates to SMART. wasn't so sure. and hence - did not look it under SMART category.
    – Royi Namir
    Apr 28 '13 at 20:06
  • 1
    Now you have two links to show your colleague though. ;-)
    – Hennes
    Apr 28 '13 at 20:07
  • 3
    But by posting it on SO many of gets to be entertained, so it's not a waste.
    – crdx
    May 3 '13 at 17:53
  • 1
    Try "searching" and transpose your finger one position to the left when you intended to type the "g"
    – Hennes
    Jun 5 '15 at 7:32

No, the temperature monitor is embedded into the HDD. It's a more recent addition and you will only see it with some of the newer SCSI disks. Anything older than a few years won't have the sensors.

It's actually a part of the S.M.A.R.T. suite that reports around 30 attributes. (http://www.hdsentinel.com/smart/index.php)

The software just pulls it from the hardware. You won the argument.

  • 1
    I don't understand. SMART has been for years now. are you telling me that only the new drives has sensors ? I have a 5 years old drive which I can tell its temperature....please explain.
    – Royi Namir
    Apr 28 '13 at 20:08
  • 6
    It's an infrared thermometer. It's integrated in the hard drive. I used to have to replace them all the time when they used to have a high failure rate. They are pretty good now. Edit: Anything supporting SMART should have the thermometer integrated. 5 years old is not that bad. I'm talking about 10-15 years old.
    – Will
    Apr 28 '13 at 20:08
  • 10
    Consumer hard drives started including temperature sensors in 2008. Before that, PCs typically had no hard drive temperature sensors and Macs typically had a sensor bonded to the outside of the drive. Modern drives have a sensor bonded to the inside of the drive casing. Last I checked, most hard drives used thermistors because there was no device already bonded to the inside of the case and a thermistor is cheap if used alone. SSDs typically use silicon bandgap temperature sensors integrated into the controller, cheap because no additional device is needed. Apr 28 '13 at 20:31
  • @DavidSchwartz, @ WillBeninger, So in such cases whereby the info cannot be found in SMART parameter, what do they use to tell the temperature?
    – Pacerier
    Jun 5 '15 at 6:11
  • @Pacerier If there is no hardware temperature sensor, then the temperature cannot e reported. Jun 5 '15 at 15:19

all the software uses statistics about heat from the RPM info"

Hard disk drives spin at a constant rate (usually 5400 RPM, 7200 RPM, 10000 RPM, or 15000 RPM). So the statistics on RPM info will probably be of little value for determining temperature.

  • 2
    Obviously the higher the RPM the cooler the drive is, since the faster-spinning platters fling the heat off of the surface with much greater force than the slower platters. /s Apr 29 '13 at 15:51
  • @Justinᚅᚔᚈᚄᚒᚔ I would upvote that, but I'm afraid that future visitors might think you're serious. :)
    – Moshe Katz
    Apr 29 '13 at 19:36
  • @Justinᚅᚔᚈᚄᚒᚔ, Well, how about more speed = more energy usage = more heat output?
    – Pacerier
    Jun 5 '15 at 5:46
  • @Jerry, "probably" is not ok. Citation please.
    – Pacerier
    Jun 5 '15 at 5:48
  • More speed and same generation might mean more heat. But it is certainly not true everywhere (e.g. modern helium filled drives with less friction).
    – Hennes
    Jun 5 '15 at 7:34

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