Mac OS X Hacks

Turning Your Mac into a Hard Drive

Boot your Mac in target mode and treat it like just another FireWire drive.

I got my brand-spanking-new 800MHz iBook the other day. I was short on time — finishing this book, in fact — but couldn’t wait to make the switch from my existing Mac to my sleek, snappy bundle of OS X joy. How could I move all of my applications and home directory (/Users/rael)? I could do without the eternity I’d have to wait transferring it over the network. I didn’t relish the number of CDs I’d have to burn to bring across all 3 gigabytes. And the idea of picking through the clutter on my external FireWire drive to make room left me ill.

If only I could mount my old machine’s hard drive alongside the new one without tools and duct tape. Surely I could just treat my old Mac as a hard drive somehow. I sure could, and did.

It turns out you can mount one Mac’s hard drive onto another Mac over FireWire quite easily. You simply tie them together with a FireWire cable and reboot one of them with the T (for target) key held down.

Tip

This assumes, of course, that you have a FireWire-capable Mac on both ends.

After just a few seconds, my old machine booted into what’s known as target mode, the screen blinking a FireWire logo where usually there’d be a Mac OS X login screen. A click, spinup, and whirr later, my old hard drive showed up right on my new Mac’s desktop.

Thanks to Macintosh’s tradition of not spreading installed software all over the hard drive, I was able to drag ...