Is Erase and Install a Safe Choice ??

[fab5freddy]

I am about to sell my Mac Pro Tower and
am going to do an Erase and Install of OS X Leopard....

Is the erase pretty safe in terms of deleting all my sensitive data ?

I mean , is it safer to do an erase first , then install ??

Thanks ! FF

 

[spinnerlys]

The data will still be recoverable after a "simple" erase and install.

You could do a Secure Erase while you're in the installation process with the help of Disk Utility.

from http://www.ehow.com/how_4815466_os-x-hard-disc-volume.html



To get into Disk Utility while booted from the installation DVDs:

Insert the Mac OS X Install disc that came with your computer,
then restart the computer while holding the C key.

When your computer finishes starting up from the disc, choose Disk Utility from the Installer menu. (In Mac OS X 10.4 or later, you must select your language first.)

Important: Do not click Continue in the first screen of the Installer.

If you do, you must restart from the disc again to access Disk Utility.


from http://support.apple.com/kb/TS1417

 

[fab5freddy]

THanks for the Quick Reply !

 

[xraydoc]

7-pass and 35-pass will take a LONG time, by the way. If you're that security-conscious (if it even helps), be prepared for it to take a long time to finish (5+ hours for high-capacity hard drives).

 

[fab5freddy]

How long does Zero Out Data take with a 300 GB Harddrive ?

 

[fab5freddy]

It's Strange. Zero Out Erase took 2 hours for a 300 GB drive !

Is that normal ?

 

[DarkJaye]

It's Strange. Zero Out Erase took 2 hours for a 300 GB drive !

Is that normal ?

The poster above was talking about the 7-pass and 35-pass options taking a long time, the normal zero out erase is the quickest secure option.

If you had picked the 7-pass erase, it would've have taken you 7 times longer to erase the data, because it essentially overwrites the drive with 0's 7 times, instead of just once.

I'm personally not that paranoid (and don't have data that I consider to be sensitive enough for a 7-pass erase) so a single zero out erase is fine for me.

 

[Jethryn Freyman]

It's Strange. Zero Out Erase took 2 hours for a 300 GB drive !

Is that normal ?

Yes.

I'd recommend a 7 pass erase though, if you really do have sensitive information there.

If someone is likely to be willing to use a magnetic force microscope to try to recover your data, you need a 7 pass erase.

 

[xraydoc]

If someone is likely to be willing to use a magnetic force microscope to try to recover your data, you need a 7 pass erase.

Exactly. For most people, this is not a likely scenario. This is why single zero pass is sufficient for most.

 

[Imola Ghost]

I was going to zero out a hard drive that I sold and I chose the 7 pass. When it was finally done calculating the time, it was like 2 days!

This was on a 500gb hard drive.

 

[fab5freddy]

And you spent 2 days doing this ??

 

[spinnerlys]

And you spent 2 days doing this ??

You have to consider, that with a 7-Pass Erase, 465GB (on a 500GB drive - which is 465GB in reality, or 500.000.000.000 bytes) will be written seven times onto the HDD. That's 3.18TB in 48 hours with a write speed of 19.3MB/s, which should be USB 2.

465GB * 7 writes / 48 hrs / 60 min / 60 sec * 1024 (factor for getting from GB to MB) = 19.288888