DeadMacFilter: Will Target Disk mode screw up my healthy computer?
August 3, 2008 8:22 AM   Subscribe

Dead hard disk on a G3 iMac. Seemingly healthy 2nd-hand G4 iMac. If I try to access data on the dead machine via target disk mode, is there a chance—any chance at all—that I could screw up the healthy machine?

(Note: I’m a total computer illiterate. Or rather, I have been a total computer illiterate—I don’t want to be any more. So, apologies in advance for obvious dimness.)

My long-ailing ancient iMac finally bit the dust. Can only boot from the (OS 9) system disk; hard drive won’t mount. Ran Disk Repair: “MountCheck found serious errors.” Tried to repair many times: no go.

Now, this isn’t a terrible tragedy. I knew the old guy was on its last legs. I have back-ups of pretty much all my important files—on CDs and on my work computer. It isn’t worth it to me to pay for a data recovery service. I don’t even want to spend the money and the effort to get Disk Warrior. But there were some photos and documents on the G3 that I don’t have a copy of. Nothing essential, but it would be nice to have them back.

I hadn’t saved up enough to buy to the new machine I wanted, but I got a really good deal on a refurb G4 iMac (800 MHz, PowerPC, running Tiger), which I figured would keep me going for the time being. And actually, I like this computer a lot. I want to keep it healthy as long as possible.

So: I have a working computer, a dead computer, and a FireWire cable. Trying to mount the hard disk on the working machine with target disk mode looks relatively straightforward, even for someone like me. I’m not holding out much hope that I’ll be able to get the files, but I’d like to try one more thing before I give up.

But before I do this, I want to be totally, absolutely sure that this won’t cause any unforeseen problems on the healthy machine. I know it’s no spring chicken itself. I have a 60-day hardware warranty and no system disk for the G4. I really, really don’t want to screw it up. (I don’t care what happens to the G3, and I’ve pretty much given up the data for lost, so no worries on that end.)

Can someone who knows something about all this either reassure me or warn me off? Many thanks.
posted by neroli to Computers & Internet (7 answers total)
Best answer: I can't imagine anything bad happening, unless you had a virus or something on your old Mac, but I highly doubt that you do.
posted by InsanePenguin at 8:44 AM on August 3, 2008

Best answer: What InsanePenguin said, but if your hard drive is dead, I don't know if it will work.
posted by chillmost at 8:52 AM on August 3, 2008

Best answer: since a virus on a mac is pretty unlikely, I can't imagine this will hurt the G4. Can't hurt to try, but don't get your hopes up.. I've not been successful in situations like this in the past..
posted by HuronBob at 9:19 AM on August 3, 2008

Best answer: No chance of problems, you're safe. Although the chances of recovery under this situation seem slim.
posted by outlier at 9:21 AM on August 3, 2008

Response by poster: Wow, thanks all. It actually worked. I got my files. I can't believe it--I didn't think it would work either. (There was a scary moment when I tried to view the G3 disk in order of file size: got the spinning beachball, wouldn't stop, tried to relaunch finder, finally just yanked the FireWire cable. All seems fine now.)

So now that I know my files are potentially accessible, I suppose I should re-initialize the hard disk on the old Mac before I junk it, right?
posted by neroli at 10:17 AM on August 3, 2008

FireWire Target Mode allows you to treat a Mac like a big, dumb FireWire hard drive. No chance of it hurting another machine.
posted by porn in the woods at 10:28 AM on August 3, 2008

You should reformat with the "Advanced" option for "zero all data" enabled, yes. If you're extra worried, there's a "zero all data by writing over 10x" option or something in there too. You have to use Disk Utlity for this: initializing from the Finder doesn't erase.

Just re-initializing leaves all your data intact, with a note saying "this space can be reused now."

Format ≠ initialize.
posted by rokusan at 10:53 AM on August 3, 2008

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