How to check if the HDD is using 4k Advanced format in osx? thanks

Discussion in 'Mac Accessories' started by kocoman, Apr 10, 2013.

  1. kocoman macrumors regular

    Dec 26, 2007
    How to check if the HDD is using 4k Advanced format in osx? thanks
  2. Mr. Retrofire macrumors 603

    Mr. Retrofire

    Mar 2, 2010
    4 kB support is implemented in the HDD firmware. AFAIK, (Mac) OS X uses 4 kB blocks for all file systems on GPT formatted disks. That means all HFS+ startup disks on Intel Macs are automatically 4 kB block compatible.

    See also:
    Secrets of the GPT
  3. smithrh macrumors 68020


    Feb 28, 2009
    Apparently, it's *also* implemented in interface hardware.

    So, you could have a perfectly fine 4k-block-size HDD, using an up-to-date version of Mac OS X, and yet only see a fraction of the hard drive be available for storage due to an outdated USB interface chip.

    Some folks have bought bare 4TB drives, then installed them into cases with outdated interface chips, then see only 900G be available to them.

    These cases aren't necessarily old either.
  4. Almarma macrumors newbie

    Aug 23, 2011
    That's true, but there's more: the OS, when creating the partitions, has to recognize that kind of disk, and create them properly aligned.

    For example, Windows XP and Vista (without SP1) cannot create correctly aligned partitions for the AF hard disks (see the "Aligned Versus Unaligned Hard Drive Partitions" chapter in the link), and that can degrade a lot the performance
  5. ColdCase macrumors 68030

    Feb 10, 2008
    Its only windose installs that have an offset that causes performance problems that require alignment to correct (perhaps only windows XP or Vista and earlier, I dunno). Both OSX and Unix have never had an issue.

    I think the only way to determine if 4000k is in use on a Mac is to go to "about this mac" to find the disk vendor and model and then look it up in the disk vendor's data sheet. If its a 4K disk, then 4K is being used.
  6. kocoman thread starter macrumors regular

    Dec 26, 2007
    4k can be seen in windows, Linux...but nothing for osx.?
  7. brentsg macrumors 68040

    Oct 15, 2008
    Define "seen".

    Everyone just said it works fine in OSX. What else are you looking for?
  8. kocoman thread starter macrumors regular

    Dec 26, 2007
    I have an af 4k 512e drive that one USB to sata adapter works and not the other. The one that does not work will show only the 0xee gpt protective mbr partition. I just want to debug that.
  9. Dalton63841 macrumors 65816


    Nov 27, 2010

    For as long as Mac has used GUID partition scheme it has supported 4k drives. 4K drives were designed to fix the fact that standard drives were designed around sector size used for MBR.

    512e is Windows BAD implementation of supporting 4K drives.

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