Re: OT: used hard disks

On 2 July, 12:32, "neverwas" <notahasb...@xxxxxxx> wrote:
As others have pointed out it's only really high temperatures that
kill
modern drives

I don't think anyone has yet pointed to the Google study
(http://labs.google.com/papers/disk_failures.pdf) which underlined this
(and possibly required even more emphasis on the *really* high):

"Failures do not increase when the average temperature increases. In
fact, there is a clear trend showing that lower temperatures are
associated with higher failure rates. Only at very high temperatures is
there a slight reversal of this trend".
--
R

The google test was WAAAAAY too simplistic on the temp front, but then
given a sample of 100k units that is understandable.

e.g. google took SMART data which said "disk 87564 is currently at
44'C"

Which is all very well, but ...

1/ the the temp sensor is no more accurate than any other LM type mobo
temp sensor.

2/ the temp sensor reading assumes the entire physical drive is at the
same temperature.

3/ the temp sensor is not placed in the worst hotspots.

a thermal image of a hard disk shows just as much difference as of a
person outside in winter in warm clothing, in practice an "average"
SMART hard disk temperature reading of say 55 degrees can easily mean
that certain components are running at 90 degrees or more.

when you remember that the point at which electronics "burns up" is
usually around 150 to 175 degrees C, you can see that it is easy to
get that 90 degree hotspot up to burnout point simply by wrapping it
is something insulating, like fluff.

Laptop type HD will get rid of heat better and thus tolerate allegedly
higher temperatures, because the MAXIMUM distance from any point in
the disk to the outside is about 4mm, as opposed to 10mm or more for a
full size disk, thin stuff dumps heat better than blocks.

I'll say it again, I have NEVER had a heat death on one of my own hard
disks on stuff I build for myself, because I ALWAYS have forced air
cooling on both sides of the HD on everything I build.
.

Relevant Pages

  • Re: Why magnetic drums was/are worse than disks ?
    ... Afair the optical path length changed both due to increasing temperature stretching the fiber, and a change in the quartz glass itself, which worked in the opposite direction. ... I gather the above is with respect to the question of whether concurrent data transfer from/to the existing multiple heads on a disk arm assembly might be feasible (while sticking with a single head per platter surface, since simple geometry tends to require this). ... If air flow between platters is negligible, this adds time to warm-up and cool-down periods, during which heat will presumably work its way through the platter stack resulting in significant temperatures differentials between outer and interior members (and consequent track-radius variations within a nominal cylinder) until everything stabilizes. ...
    (comp.arch)
  • Re: Change to a larger hard disk
    ... The product includes a power supply to operate the drive. ... Some disk drive makers, provide copying utilities. ... Is there any way to know if the computer can support upto 250 GB? ... If the old drive supports SMART, you can use the temperature display on ...
    (microsoft.public.windowsxp.hardware)
  • Re: Sun Ultra5 scsi ! Some little problems
    ... interesting, you might like to take a look at this, which is a shell script I wrote to check disk temperature. ... If within 4 degrees C of the maximum temperature it issues a warning in syslog. ... gcc hdtemp.c -o hdtemp ... # memset(&ucmd, 0, sizeof (ucmd)); ...
    (comp.sys.sun.hardware)
  • Re: slow startup on cold days
    ... >>of was a hard disk bearing going bad. ... There is not much heat at night, and so the temperature ... not familiar at all with the Windows operating system, ...
    (comp.sys.ibm.pc.hardware.misc)
  • Re: Why magnetic drums was/are worse than disks ?
    ... To tune it, I heated the fiber, and with about 1 m of fiber inside the ... Afair the optical path length changed both due to increasing temperature ... data transfer from/to the existing multiple heads on a disk arm assembly ... its way through the platter stack resulting in significant temperatures ...
    (comp.arch)