At Fri, 12 Aug 2011 22:35:12 +0100 (BST) CentOS mailing list <centos@xxxxxxxxxx> wrote:
>
> On Fri, 12 Aug 2011, Robert Heller wrote:
>
> *snip*
>
> >>> The disk's *firmware* updated itself. So long as the *disk* is powered
> >>> up and spinning, its *firmware* is 'running' (or runs when the disk is
> >>> accessed or something like that). Modern disks are a long, long way
> >>> from the simple MFM drives of the 1970s (which presented little more
> >>> than a buffered interface to the drive mechanism and read/write heads
> >>> to the host controller -- eg little more than a simple floppy disk
> >>> drive) -- modern disks have actual embedded micro-processors on them
> >>> doing various stuff, including monitoring and logging things like
> >>> sector errors, drive temp., and so on.
> >>
> >> So does accessing some of the smart data cause any disk i/o
> >> at all, or is this all done from directly firmware?
> >
> > Depends. Some of the SMART information is stored on special sectors of
> > the platter (sectors that are not part of the sectors available for
> > normal use). Some of the information is fixed burned into the
> > (E*)ROM(s) (eg serial numbers) on the disk's logic board and some
> > information is 'live' (eg current disk temperature). There IS I/O
> > between the host system and the disk's logic board.
>
> Thanks Robert. Reason I ask is because I'm using GKrellM to
> monitor my HDD temperatures. So I just wondered if querying
> the HDD temps to often would create more disk i/o ?
I believe the HDD temps are a 'live' sensor reading. The firmware might
log record/excessive high temps to a reserved sector as part of the
disk's long term health status, but it is unlikely to be constantly
logging routine temperatures.
>
> Kind Regards,
>
> Keith Roberts
>
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--
Robert Heller -- 978-544-6933 / heller@xxxxxxxxxxxx
Deepwoods Software -- http://www.deepsoft.com/
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