Disk 'heartbeat' while USB drive/card is mounted

Discussion in 'macOS' started by rshanahan, Jun 29, 2009.

  1. rshanahan macrumors regular

    Dec 24, 2007
    North East, MD
    I just noticed this strange thing a couple of weeks ago and just found the cause. Note I'm running a Mac Pro w/4 drives, 1 of which is dedicated Time Machine drive. Usually the system is dead quiet (disk activity as well) except when I am actually doing something or time machine is backing up. I have also noted what spotlight 'sounds' like when it's doing a background index.

    This 'heartbeat' is a click, click, thump, thump (I just used those terms to describe two distinct sounds, referring to disk access/seeking). It will do this FOREVER every 2-3 seconds. I have closed everything, looked at activity monitor, quit things that I thought might be causing it with no help. Note with the 'thump' there is an ever so slight increase in 1 of the cpu monitors.

    Anyway, tonight I just decided to dig more in to it Because I have 4 drives I decided to at least dis-mount 3 of them to try to determine which drive was actually getting accessed. That's when I noticed I had a cf flash card mounted in my card reader. I dismounted that 1st and, well, the drive access stopped!

    I re-inserted it and it started up again. I inserted a different (SD instead of CF) card and it also started again.

    I've never noticed this before. Any idea what would be monitoring a mounted flash card?

    Further investigation revealed that it also does it with USB 'thumb' drives and USB 'hard' drives.

    BTW, I'm on 10.5.7 if that matters. Now that I know WHAT is wearing out my drive seek mechanism, I can stop it by ejecting any removable media!

  2. LtRammstein macrumors 6502a


    Jun 20, 2006
    Denver, CO

    The noise is coming from one of your internal drives or from that card slot? I'm so confused...
  3. fcamilleri macrumors member

    Jun 7, 2009
    In Your Mind
    Call your friendly neighborhood exorcist before all your important data is projectile vomited across the room
  4. rshanahan thread starter macrumors regular

    Dec 24, 2007
    North East, MD
    Maybe it's gremlins, but I swear I didn't feed my Mac after midnight.


    Anyway, it is actually one of the hard drives being accessed when a usb device is plugged in. I'm guessing something is polling the devices when they are plugged in and updating a file or log.

    Being in the IT industry for almost 30 years in computer repair had me wondering whether one of the hard drives was beginning to fail (having errors or 'retries'). I'm glad it's just the usb ghost and not a failing hard drive.

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