How to wipe SSD before selling laptop?

Quote from boltman2007 : Yes it will. You don't know what you are talking about.

Orly?

http://news.techworld.com/securit...hers-find/

Quote : Going a stage further, they removed the drive from the PC and connected a ‘write blocker’, a piece of hardware designed to isolate the drive and stop any purging of its contents. Incredibly, after leaving this attached for only 20 minutes, almost 19 percent of its files had been wiped for good, a process the researchers put down the ability of SSDs to initiate certain routines independent of a computer.

So yes, once the SSD receives the TRIM command it will continue to purge the marked sectors as long as the drive has power, regardless of what Windows is set to.

At least attempt to backup your claims.

Quote from brbubba : Orly? http://news.techworld.com/securit...hers-find/ So yes, once the SSD receives the TRIM command it will continue to purge the marked sectors as long as the drive has power, regardless of what Windows is set to. At least attempt to backup your claims.

Windows 7 Nativity supports SSD's... so if you issue a command to stop TRIM it stops. What is so hard to understand there?
There is an on/off switch. Yes if you turn it on and remove from the PC then Windows 7 cannot turn it off.

Everything you show is assuming no on disabled TRIM and then again some data remained.
Also not all SSD controllers support TRIM and only true deletes or formats start TRIM not a delete going to Recycle bin.

So to be sure my method is still the best.

LOUD NOISES!

I Love Lamp..

Quote from boltman2007 : Windows 7 Nativity supports SSD's... so if you issue a command to stop TRIM it stops. What is so hard to understand there? There is an on/off switch. Yes if you turn it on and remove from the PC then Windows 7 cannot turn it off. Everything you show is assuming no on disabled TRIM and then again some data remained. Also not all SSD controllers support TRIM and only true deletes or formats start TRIM not a delete going to Recycle bin. So to be sure my method is still the best.

Prove it! Seriously. You haven't done a single bit of homework here to prove your position. There is no TRIM stop command within Windows. That option you showed is to disable TRIM, not to issue a TRIM stop command.

This isn't rocket science here. And sorry what was that "best" method you were espousing? Oh you mean the method were you encrypt your data or simple don't store your data on the drive at all... Oh yeah, I forgot, the user never did that so we can throw that out the window.

http://www.dfrws.org/2011/proceedings/17-349.pdf

Now read the PDF....

If you are running Windows 7 on an Intel TRIM SSD then YES data recovery is near impossible.

Other manufactures... as much as 20% of small files recoverable after TRIM even on Windows 7

The OP is using Mac.

Linux is not as good at trim support as Windows 7 so likely some data recoverable.

Quote from boltman2007 : http://www.dfrws.org/2011/proceedings/17-349.pdf Now read the PDF.... If you are running Windows 7 on an Intel TRIM SSD then YES data recovery is near impossible. Other manufactures... as much as 20% of small files recoverable after TRIM even on Windows 7 The OP is using Mac. Linux is not as good at trim support as Windows 7 so likely some data recoverable.

That article is actually the best I've seen on this topic, very interesting. Thanks for the link. However, it doesn't much help your argument since the article states,

Quote : The advent of the TRIM command has made data recovery all but impossible using current techniques. Our data shows that when TRIM is enabled, in most cases no data is recoverable.

Yes, there were some isolated cases where they could recover some small file data (900k) deleted files and doing a quick format was almost 100% effective in all drives using TRIM. Also it's not explicitly stated, but you can infer that they did data recovery immediately after the format or deletion.

OS X has TRIM support built in, but it doesn't enable by default. I think my original statement is still a fairly safe one.

Quote : Not necessary if you have TRIM enabled. Any data that has been formatted and/or deleted will be wiped out by TRIM making it non-recoverable. If you're the paranoid type then I would run an erase utility even though it shouldn't necessary.

Something very interesting did crop up toward the end of the article,

Quote : To test this theory, we used the open source tool hdparm and a short bash script to sanitize a drive in about 20 s. Due to caching and in-memory execution, this script also functions on the OS boot drive. After running the test on the boot disk and rebooting, the disk failed to mount and further analysis of the disk showed it to be completely sanitized. The execution of such commands could be automated and permit individuals to clear disks rapidly on demand or to trigger the action based on a series of events. Such automation may result in first responders encountering a completely sanitized disk.

Although in this case all hdparm is doing is triggering the TRIM command at will.

I sold the laptop today (for the second time. First buyer didn't pay, but the second one did already.)
I need to take of everything tonight, so what is the consensus on what I should do? Just wipe it once?

If I delete files, empty the recycling bin (or even "secure empty"), and then wipe the drive, will that benefit me at all? (Versus just wiping the drive without deleting anything.) Sorry if that's a dumb question.

Thanks!

You could boot the laptop from the OS X DVD and use the Disk Utility to do a Secure Erase. You can choose 1, 3, or 7 pass wipes. I'd say 3 is prolly enough, but 7 would be more secure.

Quote from boltman2007 : Windows 7 Nativity supports SSD's... so if you issue a command to stop TRIM it stops. What is so hard to understand there?

how about the part where lion is installed, and lion will be re-installed, and by the time you get to your windows 7 install, the data will be gone?

Quote from heavylee : You could boot the laptop from the OS X DVD and use the Disk Utility to do a Secure Erase. You can choose 1, 3, or 7 pass wipes. I'd say 3 is prolly enough, but 7 would be more secure.

Multi passes on standard drives are fairly useless and on SSDs are truly and completely pointless.

OP, 1 pass should be more than enough, my only issue is that the os x disk utility isn't going to support TRIM. Ideally you'd like a utility that supports TRIM and will do a quick format. A secure delete of an SSD should only take about 20 seconds according to the research paper. Only problem is that I can't find a tool that's guaranteed to support TRIM.

Using the disk utility single pass should do a good enough wipe where most normal individuals could not recover any data easily.

EDIT: BTW, I found the command to use for HDPARM, which is what the research paper used. You can just make a parted magic boot disk to use the utility from the command line.
https://wiki.archlinux.org/index....l_Clearing

Secure Erase is disabled for SSDs in lion! I have currently erased my partition after booting into Disk Utility. Lion is currently downloading from online restoration.

What else should I try? What if I copy a ~4GB movie file to the fresh installation, copy it to file the 120GB drive, and then delete all of the copies using "Secure Empty Recycle Bin"? Will that help?

Quote from akkkmed : Secure Erase is disabled for SSDs in lion! I have currently erased my partition after booting into Disk Utility. Lion is currently downloading from online restoration. What else should I try? What if I copy a ~4GB movie file to the fresh installation, copy it to file the 120GB drive, and then delete all of the copies using "Secure Empty Recycle Bin"? Will that help?

Yep, it ain't so easy. Here's another guide and the consensus seems that to do a real erase you need to use hdparm with a boot CD. http://forums.macrumors.com/showt...p?t=841182

In your case though I would either take your 4GB file and make copies until the drive is full then just erase them. Otherwise, without that linux boot disk, your only other option is to encrypt your entire drive then lose/delete the encryption key.

This is pissing me off. Lion Internet Recivery wouldn't work. I won't explain why.
So now I'm reinstalling Snow Leopard via disk. Then I'll have to download Lion AGAIN and install. So much time has been wasted because of the errors. Only good news is that SL disk let me write zeros...

As I type this, SL seems to be stuck at 32 minutes remaining. What the hell is wrong??? I need to ship it out tomorrow!

I finally got everything working.
-Erased partition
-Erased drive
-Wrote zeros to drive (one-pass)
-Installed Snow Leopard from restore disks
-Downloaded Lion from App Store
-Installed Lion