Security of Data on Disk: HDD vs. SSD

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Here's a rather interesting video that explains the difference between the way files are handled on a hard drive versus a SSD. While this may be common knowledge to you and I, this is a great video to forward to your friends and family that aren't as tech savvy.
 
That's a great little video - I think I will use that when I teach the next A+ class.
 
Not something that's uncommonly known in the PC world, with Flash Vs Physical storage. It's nice to see it put elegantly.
 
Really well worded. Entertaining to watch during my lunch :)
I have a handful of people working for me that watching these would benefit.

Good find Steve. GCG 9.8 ;)
 
Sigh. This actually isn't very good.

#1, you don't need to overwrite a HDD multiple times. A single overwrite will do the trick on any modern EPRML drive. The analogue waveform and encoding are far too complex for anyone to get anything from it. It was only back in the FM/MFM days when you could potentially read previous signals. It just doesn't work with the nature of EPRML. One overwrite will destroy it.

#2, if you are going to tell people about the fact that flash doesn't work the same, tell them what to do instead! The answer is to run an ATA Secure Erase. Parted Magic is a bootable Linux ISO that can do that for you. It is a special command, part of the ATA command set, that you issue to the drive. The controller will then go and blank the entire flash, overprovision area and all. Everything is completely erased. Also, it restores the drive to factory performance, since all flash is now empty. So useful to do prior to a reinstall or the like.

Also, #2.5, you can run secure erase on HDDs too, and it'll erase everything, including bad sectors.

So ya, don't run DBAN on flash drives, but let people know what they can do. Really the solution now, magnetic or flash, is secure erase. It blows away everything, and does so at the low level because it is a command directly to the controller, which then handles the details.
 
Sycraft said:
Sigh. This actually isn't very good.

#1, you don't need to overwrite a HDD multiple times. A single overwrite will do the trick on any modern EPRML drive. The analogue waveform and encoding are far too complex for anyone to get anything from it. It was only back in the FM/MFM days when you could potentially read previous signals. It just doesn't work with the nature of EPRML. One overwrite will destroy it.

#2, if you are going to tell people about the fact that flash doesn't work the same, tell them what to do instead! The answer is to run an ATA Secure Erase. Parted Magic is a bootable Linux ISO that can do that for you. It is a special command, part of the ATA command set, that you issue to the drive. The controller will then go and blank the entire flash, overprovision area and all. Everything is completely erased. Also, it restores the drive to factory performance, since all flash is now empty. So useful to do prior to a reinstall or the like.

Also, #2.5, you can run secure erase on HDDs too, and it'll erase everything, including bad sectors.

So ya, don't run DBAN on flash drives, but let people know what they can do. Really the solution now, magnetic or flash, is secure erase. It blows away everything, and does so at the low level because it is a command directly to the controller, which then handles the details.
Click to expand...

Uh. No. Your still wrong though. You need a few passes of random data to "scrub" it from existence. Even then, it's still theoretically possible from what I'm seeing here.
http://en.wikipedia.org/wiki/Gutmann_method

"For any modern PRML/EPRML drive, a few passes of random scrubbing is the best you can do"

Notice how he says "best you can do" not "Adequately protect yourself"

SSD's do poses a serious problem if the encryption isn't strong enough. Say someone builds a master key into the sandforce encryption? what then?
 
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