Delete does not equal erase – Part Deux

Doug followed up his “Delete does not equal erase” post yesterday, with an email to me. This essentially said, “Pete, you have a Mac, could you do a quick post on how to do the same thing on your ‘Cult of Steve Jobs’ machine?”. I’m not going to reiterate the reasons for wanting to do this, as these were covered in the original post. But here are the mechanics of it.

A Mac, is actually built upon another great operating system – FreeBSD. So, in addition to having access to some useful utilities in OS X, you also have access to standard BSD programs. So, let’s start with the GUI tool Disk Utility. ┬áThis can be found in /Applications/Utilities/, and when opened, you are presented with the main window. Select the drive to be erased, select “Erase”, and click “Security Options”.

Disk Utility - initial options

The Secure Erase Options window will open, with various options available. In this case, we want to select “Zero Out Data”, and click OK.

Disk Utility - selection of secure erase option.

You will now be back at the original screen. Select “Erase”, then “Erase” again.

Disk Utility - Erase

You are now back at the orinal screen, with the addition of a progress bar. Once this has run its course, the progress bar will disappear.

Disk Utility - progress bar

Your disk is now securely erased.

Disk Utility also has a command line version called “diskutil”. The first step in using this, is to open a Terminal window. Again, Terminal can be found in /Applications/Utilities/. Once open, diskutil can be called, with any options you wish to be parsed with it. Firstly, we identify the disk we want to erase.

diskutil - identify disk for erasure

In our example, we pass the arguments: “secureErase”, “0” (overwrites with zeros), “/dev/disk2”. We are then presented with a progress bar.

diskutil - erasing with zeros

When progress is complete, we again have a securely erased drive.

Finally, as with most *nix operating systems, or by using DD for Windows, we can use the “dd” command line utility. In this case we can use the diskutil list command (see previous), to again identify the disk we wish to erase, and then pass the command line arguments to dd.

DD - writing zeros to disk2

In this case, there is no progress indication, so you just have to wait until the command prompt returns.

So end this post. We eagerly await Doug’s post on proving that the drive is now “zeroed”.

Delete does not equal erase – Part Deux

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