Secure Empty Trash or ??

[Apple Corps]

I have about 60 GB of data on a new 750 GB drive that I want securely erased as I am passing that drive on to someone else.

Zero out the drive or do a 7 pass is secure BUT takes a long time for 750 GB

What if I drag those files to trash and do a SECURE EMPTY TRASH - much quicker as I am not writing 750 GB of zeroes but is it as secure?

 

[spinnerlys]

I have about 60 GB of data on a new 750 GB drive that I want securely erased as I am passing that drive on to someone else.

Zero out the drive or do a 7 pass is secure BUT takes a long time for 750 GB

What if I drag those files to trash and do a SECURE EMPTY TRASH - much quicker as I am not writing 750 GB of zeroes but is it as secure?

Yes. That will work too. Even a 1-pass (Zero Out) is sufficient.

 

[synth3tik]

secure empty over writes the data with zeros instead of just marking it as free space. I would still do a 1 time pass over the entire drive. Also if your about to call it at night, might as well set up for a 7 time pass, by the time you awake in the morning it would be done and all would be good.

 

[Apple Corps]

So am I understanding this correctly:

Reformatting the drive simply destroys the directory but the data is still there - crafty people can restore the directory and get your data - low security

Dragging the data to the trash and simply emptying the trash destroys the directory but the data still exists - low security

A SECURE EMPTY TRASH destroys the directory and overwrites the data with 0s - much more secure erasure of the data

A SECURE EMPTY TRASH AND erase drive with a multiple overwrite of 0s is way more secure - may give the CIA or Criminal Minds Staff a run for their money as the magnetic ghost of the data is lost to the multiple 0s being written

How close am I to understanding it?

 

[spinnerlys]

You have understood it just fine. But you can save the last SECURE EMPTY TRASH step if you also do a 7-pass with Disk Utility.

Btw, Disk Utility offers to Free Space with ZERO OUT, 7-PASS or 35-PASS overwrite options. So you can delete your files normally, empty the trash normally and then use Disk Utility to erase free space with one of those options.

 

[Apple Corps]

spinnerlys - thanks - I think on my 750GB drive I will SECURE EMPTY TRASH the 50 or 60 GB of data and then do a 1 pass zero overwrite. It really does take a lot of time to write all those zeros

 

[Apple Corps]

One pass on a 750 GB drive was over 4 hours - forget about a 7 pass erase

The write speed to that drive was at 50 MB/s or 3000 MB/minute or 3 GB/minute

So - 750 GB ÷ 3 GB/minute = 250 minutes = 4.167 hours.

 

[OldSchoolMacGuy]

I've seen cases where even after a single pass with Disk Utility, some files are still recoverable. This isn't to say that for the uses of most, single pass shouldn't be enough, just that Disk Utility isn't the best option for shredding a drive.

 

[Apple Corps]

I've seen cases where even after a single pass with Disk Utility, some files are still recoverable. This isn't to say that for the uses of most, single pass shouldn't be enough, just that Disk Utility isn't the best option for shredding a drive.

On one of my smaller drives I've done a reformat and 4 passes writing zeros - that I am very confident on having nuked the data. The 35 pass option - yikes - that option sounds like mega overkill

 

[iHateMacs]

Who would need 35 passes? If anyone was THAT paranoid wouldn't it be cheaper and quicker to take the drive out, remove the platters and attack them with a large hammer? I'm sure even the FBI would struggle to recover anything from that.

 

[koruki]

35 passes and take it out finish off by drilling holes through out before setting it on fire please. ahh now i feel safe.

 

[Apple Corps]

35 passes and take it out finish off by drilling holes through out before setting it on fire please. ahh now i feel safe.

But then you have to sweep up the drill shavings and melt those as well

I agree - reformat and a pass or two should be good for 99.9999% of situations.