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

    Oct 16, 2008
    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 ?

  2. hokan macrumors member

    Mar 18, 2014
    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.

  3. MorphingDragon macrumors 603


    Mar 27, 2009
    The World Inbetween
    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.

Share This Page