What steps should I take (privacy-wise) before bringing my iMac in for HDD swap?

[Whackintosh]

Now that I've got my new 2012 iMac set up, I'm going to bring my old 2009 machine in for the Seagate replacement program service. If I completely erase the contents of my drive, they'll have no way to verify my serial number, right? So, I presume I shouldn't fully erase my drive. Is there a way to securely erase everything except for the basic "about this Mac" information?

 

[simsaladimbamba]

The serial numbers of the HDD and of the Mac are visible without any of your data on the HDD or even after wiping it, since the serial number is not stored in a file, that you can delete in any way.

 

[marzer]

Now that I've got my new 2012 iMac set up, I'm going to bring my old 2009 machine in for the Seagate replacement program service. If I completely erase the contents of my drive, they'll have no way to verify my serial number, right? So, I presume I shouldn't fully erase my drive. Is there a way to securely erase everything except for the basic "about this Mac" information?

No. That information is available on the hardware devices, they don't need to boot it to confirm eligibility. In fact, the SN for the computer is on the underside of the stand. I wiped my hard drive before taking it in for replacement under that program.

 

[Raima]

There are recovery tools that can recover data that has been deleted or drives that have been wiped.

There is a erase function in disk utility that wipes the drive and zero outs the drive. There's a thorough method that does it 7 times or something.

That's the option that needs to be selected if you're concerned about privacy and ensuring no data that was previously on the drive can be recovered.