iMac Reformat hard drive before selling
When preparing my iMac for sale, I followed the relevant pages on apple.support.com pages. When it came to the actual reformat action, I chose a security option that overwrites the contents with two passes of random data then a single pass of known data over the entire disk and expected it to take a long time (having done something similar some years ago on a PC). Disconcerted to see that the whole process of reformatting and overwriting took much less than a minute. Decided to repeat the process, this time choosing the highest level of security (DOD 5220-22M which erases data then overwrites seven times) - which also took a very short time. Can this be right?