Why can't I find 'load cycle count' for MyPassport Hdd ?

Discussion in 'Mac Programming' started by XPcentric, Apr 7, 2014.

  1. XPcentric macrumors 6502

    Joined:
    Oct 16, 2008
    #1
    I have an external MyPassport (WD HDD), and it has two partitions, FAT32 and OSX default partition. I checked with Disk Utility and its written S.M.A.R.T not supported.

    I would like to know if there is any way I could find the health of this HDD. The reason why I can't is it because the way it is made or because I've done the partitions ?

    Regards!
     
  2. hokan macrumors member

    Joined:
    Mar 18, 2014
    Location:
    Sweden
    #2
    S.M.A.R.T. support shouldn't be related to the number of partitions or the filesystems used on them, as S.M.A.R.T. is a feature of the actual HD/SSD.

    But there appears to be a number of scenarios when access to this information may not be available:

    Depending on the type of interface being used, some S.M.A.R.T.-enabled motherboards and related software may not communicate with certain S.M.A.R.T.-capable drives. For example, few external drives connected via USB and Firewire correctly send S.M.A.R.T. data over those interfaces. With so many ways to connect a hard drive (SCSI, Fibre Channel, ATA, SATA, SAS, SSA, and so on), it is difficult to predict whether S.M.A.R.T. reports will function correctly in a given system.

    Even with a hard drive and interface that implements the specification, the computer's operating system may not see the S.M.A.R.T. information because the drive and interface are encapsulated in a lower layer. For example, they may be part of a RAID subsystem in which the RAID controller sees the S.M.A.R.T.-capable drive, but the main computer sees only a logical volume generated by the RAID controller.

    http://en.wikipedia.org/wiki/S.M.A.R.T.#Visibility_to_host_systems
     
  3. MorphingDragon macrumors 603

    MorphingDragon

    Joined:
    Mar 27, 2009
    Location:
    The World Inbetween
    #3
    It depends.

    Most extenral HDDs simply implement the mass storage commands for USB, which is a subset of the storage commands of SATA drives excluding SMART.

    Only really high quality drives will implement the full available set of storage commands over USB.
     

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