Secure deleting a Macbook (pro) with OSX

Yesterday i was preparing my old Macbook Pro for selling, and after doing a backup i wanted to do a secure delete of all the hard disk content. So i started to search for a software or a solution (before using a live CD) and i found that the OSX include the option to do a secure delete in the "disk utility", best of all is that the cupertino boys have 3 different kinds of secure delete, with different levels of security, to prevent the file recovery.

Zero Out Data:

This method writes zeros over all of the data on the drive. This provide a decent level of file security,there are forensics utilities that in theory could retrieve some data however they are extremely expensive and time consuming and there are no documented cases of this actually taking place.

7 pass erase:

This method will write data over the disk seven times, and will take 7 times longer than Zero Out Data. This method is compliant with the D0D 5220.22-M specification, meaning that it is virtually impossible to retrieve the information.

35 pass erase:

If you are paranoid or you really need to protect some files, you can use this method that writes the entire disk 35 times... It is said that this method is really impossible to recover. Also this option will take ages to finish.

Well after checking the options, i went with the 7 pass erase method, and for a 150GB partition it took 7 hours to complete, now i had to do the same for the 100GB partition :(

Reference: http://danbenjamin.com/articles/2008/05/secure-erase-osx
-CMM