So, it took two trips to the shop to get my brand-new Quad G5 running reliably, demonstrating once again that it’s never safe to buy The Latest Thing from Apple (or, to be fair, most vendors). It works great now, and when I took it in the second time, it received automatic priority as a “looper”, so it was done in two days. That’s the good news.

Now for the bad news: this morning, my PowerBook died with repeated kernel panics (most likely bad RAM, from the symptoms). I had backups, of course, but I didn’t need them. All I had to do was carry it over to another Mac, connect them with a FireWire cable, and reboot the second Mac from the PowerBook’s hard drive. In 30 seconds I was back in business, with everything exactly the way I like it.

I immediately made a fresh backup to a portable FireWire drive, and just for good measure, stored a disk image of that backup on the other Mac’s drive. Since I still need a laptop, I’m now booting my ancient 700MHz G3 iBook from the FireWire drive, and that’s what I’ll be carrying to work until the PowerBook is fixed. It’s a lot slower, and a bit clumsier to carry around, but I don’t have to spend any time fixing preferences, reinstalling applications, etc, etc.

Best of all, everything was done with vendor-supported tools that ship with Mac OS X, without ever opening up a case. You can rescue data from a broken Windows or Linux laptop, but the process is a touch more involved (coughcough), and the odds aren’t good that you can just boot another computer from that disk.

Update: okay, there are a few things that don’t “just work” when you pull this trick. The OS stores some of its preferences on a per-host basis, keying off the MAC address on the primary ethernet port. These are stored in ~/Library/ByHost/, and include that address in their name. Most of them are pretty obvious, like network port configurations, display preferences, and iDisk synchronization, but I was surprised that it included the input menu contents for multi-language input. The menu was there, but I had to click the checkboxes to re-enable Japanese input. So far, that’s the only host-specific preference I’ve had to set.

So, add 5 seconds to the transition time. :-)

There is one annoying side-effect to this. If you’ve turned on local mirroring of your iDisk, that mirrored copy is also host-specific. It makes sense, but it means that I have a hidden disk image chewing up 1GB.