4 Replies Latest reply: Jun 3, 2006 9:51 PM by baltwo
Jim Schafer Level 2 Level 2 (315 points)
Does anyone know which "Erase" option, if any, does a true low-level format of a hard drive? The kind which flags bad sectors and updates the drives bad sector table.

In the old days, before OS X, I used to use FWB "Hard Disk Toolkit" to format my drives to insure I didn't lose any data to new and unflagged bad sectors on a drive.

But Disk Utility doesn't seem to have an old-fashioned "format with verify" mode that will do what I want. At least not labeled in a manner which allows me to understand that it is going to do that.

Anyone have any inside knowledge on this subject?

Thanks in advance.

DP 1.25 G4 w/ FCP 5.1.1, FC Studio 5, etc., Mac OS X (10.4.6)
  • 1. Re: Disk Utility - Low Level Format??
    baltwo Level 9 Level 9 (60,085 points)
    Disk Utility->select the volume->erase->security options. AFAIK, any of the bottom three automatically mark bad sectors. See the manpage for diskutil.
  • 2. Re: Disk Utility - Low Level Format??
    Kappy Level 10 Level 10 (226,685 points)
    None. You cannot low-level format an ATA drive. Low-level formatting is for SCSI drives. What you can do is zero the data on an ATA drive which will mark bad sectors if there are any.

    Do the following:

    1. Boot from your Tiger DVD. After the installer loads select Disk Utility from the Utilities menu. If this is an external drive then you can use Disk Utility from your Utilities folder rather than booting from the DVD.

    2. After DU loads select your hard drive (this is the entry with the mfgr.'s ID and size) from the left side list. Click on the Partition tab in the DU main window.

    3. Set the number of partitions from the dropdown menu (use 1 partition unless you wish to make more.) Set the format type to Mac OS Extended (Journaled.) Click on the Partition button and wait until the volume(s) mount on the Desktop.

    4. Select the volume you just created (this is the sub-entry under the drive entry) from the left side list. Click on the Erase tab in the DU main window.

    5. Set the format type to Mac OS Extended (Journaled.) Click on the Options button, check the button for Zero Data and click on OK to return to the Erase window.

    6. Click on the Erase button. The format process will take 30 minutes to an hour or more depending upon the drive size.
  • 3. Re: Disk Utility - Low Level Format??
    Jim Schafer Level 2 Level 2 (315 points)
    None. You cannot low-level format an ATA drive.
    Low-level formatting is for SCSI drives. What you
    can do is zero the data on an ATA drive which will
    mark bad sectors if there are any.


    Ah ha! I guess this shows my ignorance from 22 years as a "pure" Mac guy.

    Thanks for clearing this up.
  • 4. Re: Disk Utility - Low Level Format??
    baltwo Level 9 Level 9 (60,085 points)
    Thanks for the feedback. Good computing.