Temporarily Parking the Hard Disk Heads - Embedded

This is a discussion on Temporarily Parking the Hard Disk Heads - Embedded ; Hi, I've an embedded Linux booting from a flash disk and running on a PC104+ stack. This PC104+ computer is carried on a moving platform and occationallyy subject to high vibration. I do have know when vibrarion will start and ...

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Thread: Temporarily Parking the Hard Disk Heads

  1. Temporarily Parking the Hard Disk Heads

    Hi,

    I've an embedded Linux booting from a flash disk and running on a
    PC104+ stack.

    This PC104+ computer is carried on a moving platform and occationallyy
    subject to high vibration. I do have know when vibrarion will start and
    the duration of the vibration.

    Some time I do attach an IDE hard disk (40-160GB) to my embedded Linux
    system for high speed high volume data logging. Due to the occational
    vibration, I would like to be able to park the hard disk heads just
    before the vibration starts and re-activate logging when vibration
    ends.

    I wonder if there is a way of temporarily moving the harddisk heads to
    parking position and back?

    Thanks,

    Miem Chan
    miemchanATyahooDOTcomDOTau


  2. Re: Temporarily Parking the Hard Disk Heads

    Hello,

    > This PC104+ computer is carried on a moving platform and occationallyy
    > subject to high vibration. I do have know when vibrarion will start and
    > the duration of the vibration.


    Using a spinning hard disk, this is bad, even if put to sleep.

    > Some time I do attach an IDE hard disk (40-160GB) to my embedded Linux
    > system for high speed high volume data logging. Due to the occational
    > vibration, I would like to be able to park the hard disk heads just
    > before the vibration starts and re-activate logging when vibration
    > ends.


    I don't believe modern disks have a special "parking position" but you could
    stop them spinning.

    > I wonder if there is a way of temporarily moving the harddisk heads to
    > parking position and back?


    You can put the disk directly into standby or suspend mode using "hdparm -y"
    respective "hdparm -Y". hdparm is included with busybox, with the needed
    parameter, if I remember correctly.

    Another idea would be to set the spindown timer very low (hdparm -S), so
    that the disk spins down after maybe 5 seconds of inactivity. But you have
    to ensure that no further accesses occur. Then you only have to stop
    activity on the disk before vibrations occur. But it won't be good for your
    disk as it shouldn't vibrate while spinning...

    Hope this helps,

    Sebastian






  3. Re: Temporarily Parking the Hard Disk Heads

    On Wed, 5 Jul 2006 21:25:40 +0200, Sebastian wrote:


    >Hello,


    >> This PC104+ computer is carried on a moving platform and occationallyy
    >> subject to high vibration. I do have know when vibrarion will start and
    >> the duration of the vibration.


    >Using a spinning hard disk, this is bad, even if put to sleep.


    >> Some time I do attach an IDE hard disk (40-160GB) to my embedded Linux
    >> system for high speed high volume data logging. Due to the occational
    >> vibration, I would like to be able to park the hard disk heads just
    >> before the vibration starts and re-activate logging when vibration
    >> ends.


    >I don't believe modern disks have a special "parking position" but you could
    >stop them spinning.


    I believe they still have a parking position, but you don't have to manually
    position them. They snap the heads to a safe location using internal stored
    power when power is removed.

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