Use target disk mode to create a disk image backup

Dec 21, '05 05:16:00AM

Contributed by: sblowes

I have an old 500mhz G3 iBook with only 256mb RAM and 10gb hard drive. I've been using it since 2001, and it's a testimony to Apple that inspite of dragging it around the world with me, dropping it a couple of times it's still going strong, and actually runs Tiger, Adobe CS, Macromedia Studio MX, MS Office 2004 and Final Cut Express without any trouble. I use it every day, all day.

However, because I use it every day, it's highly tweaked, with preferences, Automator apps, crontabs and shell scripts going that I don't even remember! So I wanted a way to back it up completely, so that it if my iBook finally gives up the ghost, or if I can scrape together enough for a new iBook, I can do a restore and have my iBook running just the way I remember it -- I wanted an easy backup of the entire filesystem. Here's how I did it:

In Tiger's System Preferences, go to StartUp Disk and select Target Disk Mode. (On older systems, just hold down "T" while booting the machine.) The computer will restart. Plug in a FireWire cable and hook it up to another Mac running OS X. My iBook rebooted and had a FireWire screensaver pop up. On my G4 tower, my iBook hard drive popped up as an external drive.

Next, go to Disk Utitlity, click on the new external FireWire hard drive and File: New -> Disk Image from Disk(x). Find somewhere with plenty of space (I chose my LaCie FireWire800 external), and save the disk image in read/write format. It takes a few minutes to complete, but you then have a (mountable!) disk image storing an exact image of your hard drive.

Disk Utility then lets you use that .dmg disk image to do a restore on a new machine, which technically should be exactly the same as the first machine at the time you backed it up.

[robg adds: I thought we had a similar hint here, but I couldn't find it, so here's a possible duplicate :). Note that "a few minutes to complete" could be substantially longer than that if you have a larger hard drive. Also, I would personally not recommend restoring an image from machine X onto machine Y, unless both machines were identical (or near identical) models. Although I have no empirical evidence to back that position, it just seems like a recipe for disaster, especially as the newer machine may have hardware features that the old machine lacked.]

Comments (11)


Mac OS X Hints
http://hints.macworld.com/article.php?story=20051216132831279