Ye Macce Threade

[shellylh]

Thanks Jacob and Mark.

Ran into an annoying problem: my older 2005 tablet pc won't boot from a USB drive and doesn't have CD drive. That is annoying. Guess I'll switch the HDs in the two of them and use the newer computer to wipe it.

Edited August 1, 2015 by shellylh

[Dusty Chalk]

...my older 2005 tablet pc won't boot from a USB drive and doesn't have CD drive. 

That might be a BIOS setting -- sometimes it's set so that the hard drive boots first, I.E. always unless it fails.  Go into the BIOS settings and look for something like "boot order".  Sometimes it's order, sometimes it's on/off, sometimes it's other things.

[shellylh]

I had already checked the BIOS settings and it didn't have USB as an option like the other tablet.  I just put the older harddrive in the newer tablet pc and did it that way, they weren't very hard to get to. 

Edited August 2, 2015 by shellylh

[Dusty Chalk]

That works, too.

[shellylh]

I realized that I have to erase the hard drive on Tim's most recent computer (2014 MBP) which has a SSD drive.  The problem is that I have to give the laptop back to the department and I believe they are going to use the laptop.  I think it needs to include the SSD and even if not, I am not sure how easy it is to get the SSD out of the computer. 

 

Is there a way to securely erase an SSD without physically destroying it?  I have read that encrypting doesn't work nor does writing over with zeros.  

[Voltron]

I imagine that wiping it would be enough because nobody in the department is going to try to reconstruct his data.

[Torpedo]

I imagine that wiping it would be enough because nobody in the department is going to try to reconstruct his data.

This. I really doubt anyone is going to try.

[shellylh]

It would be much better for a random person to try to reconstruct the data because he has letters of recommendation for students who are current grad studetns, postdocs and former students (these are exactly the people who are going to have access to the computer).  While it is unlikely they would do this, graduate students in math have been known to spend endless hours doing something just because they can (and some have backgrounds in computer science).  

[skullguise]

I think wiping it with zeroes would be 100% fine, but only if you do the whole drive and not just the index/contents section.  Some programs out there will do multiple passes, too.  Not sure what is out there for Mac Wiping SW, but I have had no issues with wiping PC drives this way.

[Dusty Chalk]

 

Is there a way to securely erase an SSD without physically destroying it?  I have read that encrypting doesn't work nor does writing over with zeros.  

It is correct that encrypting does nothing, but reformatting the drive should be sufficient for everyone but a professional data retrieval type person (I.E. cyberwarfare types and hardware forensics types).  I don't think even someone like geek squad have the technology to find out what bits were on a formatted drive before it was formatted, especially if you use the long form formatting (whatever that's called in Mac/Apple-land).

 

Alternatively, you could just buy them a new SSD -- just get the same kind, and let them put the OS back on.

[shellylh]

Yeah but I don't think it is that easy to get to the hard drive in the MBP.

[Dusty Chalk]

Oh, that's right, isn't that the one with the proprietary SSD?

 

Yeah, never mind.

[shellylh]

By the way, can anyone explain why encryption doesn't work. If encryption does keep people from getting to your information, why do it? I would think it would be as good as reforming the HD.

[grawk]

do this from the command line:

 

diskutil randomDisk 2 /dev/diskN

 

That should be thorough enough that even commercial tools won't get at the data. 

 

Encryption would work fine if you started with it on.  The reason it doesn't help in this case is the same reason overwriting is a pain.  SSDs don't like to overwrite the data, they just write to new locations and change the pointer.

[shellylh]

do this from the command line:

 

diskutil randomDisk 2 /dev/diskN

 

That should be thorough enough that even commercial tools won't get at the data. 

 

Encryption would work fine if you started with it on.  The reason it doesn't help in this case is the same reason overwriting is a pain.  SSDs don't like to overwrite the data, they just write to new locations and change the pointer.

 

 

Why would writing over the drive twice work if writing over it once didn't?  Just curious. 

 

I think I made him encrypt the drive when he first got it.  If this is true, I assume it would be difficult for someone to recover the data (well, except his password is pretty easy for a computer to guess probably - would it help for me to change his main password?).

Edited August 3, 2015 by shellylh

[shellylh]

It's not very hard to get at the SSD.  Unfortunately, it's not a standard SSD that I can buy at amazon and put back in.  I suppose apple would charge me a lot to replace it.  

 

https://www.ifixit.com/Guide/MacBook+Pro+13-Inch+Retina+Display+Mid+2014+SSD+Replacement/27849

 

Damn, even from ifixit, they are charging $314.95 for a new replacement drive. 

 

Edit:  I guess Dusty already pointed this out. 

Edited August 3, 2015 by shellylh

[shellylh]

The person getting it is going to need to reformat anyway, might as well go ahead and do it for them.  Besides, some encryption routines have known vulnerabilities.  

 

I definitely would plan on reformatting it.  

[grawk]

because twice makes sure every byte of the disk gets rewritten.

 

if it was encrypted from the beginning, then just format it and you're safe.

[Dusty Chalk]

Why would writing over the drive twice work if writing over it once didn't?  Just curious. 

I am curious about this myself.  I always thought it was a hysteresis thing.  Hysteresis, is a tendency for magnetic media to retain a recording.  If you write over it once, and you know the nature of the media, you can figure out if there was a 1 or a zero underneath it based on small deviations from the value it should have been if there was never any data there to begin with.  This gets shrunk dramatically the second time, and now instead of two possible values around a known constant, you have two possible values around two possible values.  It just gets fuzzier after that.

 

Those values by the way, are pretty darn small to begin with -- one requires extremely sensitive equipment to perform data forensics.

 

And yes, they don't write constant values on any drives any more, they write patterns when they're reformatting, because it makes for a better hard disk anyway.  "Like new."

[luvdunhill]

It's because mil-spec. Has Ray been gone that long, not to remind you?!

[luvdunhill]

So what do the resident Apple zealots think of this XcodeGhost thing?

[TMoney]

So I started using the External Apple Trackpad instead of a traditional mouse at work... and its awesome!

Getting stuff done on a Mac is SO MUCH BETTER when you can use the trackpad gestures built in to the OS.

[shellylh]

I'm thinking of updating the OS on my early 2009 Mac Mini (2.26 Intel Core 2 Duo).  I just use it as a music server for my headphone setup.  I have Snow Leopard still on it but I can't run Tidal with SL.  Would it be stupid to update to El Capitan (lots of speed increases over Yosemite I have read) or should I just install Mountain Lion on it? 

[shellylh]

8GB

[grawk]

The only drawback to el capitan that I've found is that the firewire apogee interfaces aren't supported.