A few months ago, I read a forum thread about using Mac OS X Tiger on older Macs and I decided to try it with my old G3, 500 MHz iBook. I didn't think it would work but, to my surprise, I found I was wrong. My iBook has only 192 MB of RAM and the stated minimum RAM for Tiger is 256, and, initially, Tiger was more like a turtle than a cat on that old iBook. But, with a few adjustments, I found myself using my iBook as an acceptable, but slow, backup Tiger computer.

I didn't install Tiger on the iBook directly, but, rather, used a portable external hard drive as my Tiger boot drive. The old iBook has only a 10 GB hard drive and that is not enough space for even a minimum Mac OS X 10.4 system with some basic software, so I used a 20 GB external drive instead.

Once the external drive booted, I waited an endless amount of time for the system to stop spinning, and I thought "This is never going to work." It finally did settle down, and I then began disabling some of the memory hogs in Mac OS X 10.4. The first to go was Spotlight - disabled in the System Preferences Pane. Next, I used Tinker Tool to disable Dashboard. I then went back to System Preferences and set my Desktop picture to one of Apple's bland, solid colors, disabled all log-in items I didn't need and went through all the other preferences to disable any other unnecessary enhancements.

So, how did Tiger run after that? Not fast, but usable. I wouldn't recommend Tiger for an old Mac with limited RAM (Mac OS X 10.2 runs much better on my iBook), but, in an emergency, it can be used, as long as you remember to disable CPU-hungry applications and Tiger features.