I’m navigating a couple of variables here. This is the first month in which Apple might ship Tiger, the next major update to the Mac OS. It could be as late as June, of course, but I still need to stay on top of events. And I’m certainly in a good position to talk about this subject: I’m writing a book about Tiger that’s supposed to be released on the same day as the OS (look for it from Wiley Publishing), so I’ve been receiving preliminary builds for the past two or three months.

But there’s a catch: to keep these advance DVDs rolling in, I had to sign a bunch of documents that oblige me to remain mum about Tiger until it actually hits store shelves. So according to my attorney, my inner urge to write something helpful about Tiger can only find three outlets:

1) Write about what to do if you’re attacked by a tiger.
2) Write something that applies to OS upgrades in general.
3) Write something helpful about what to do if you’re attacked by any major land-based predator, not just a tiger.

I strike #1 off the list for obvious reasons. I can’t bring much personal experience to the topic, and although I’ve been Googling the subject furiously, I haven’t been able to turn up anything helpful. It turns out that tigers are really, really good at attacking people; apparently, they never leave a job half-finished. So any ideas on surviving a tiger attack are frustratingly speculative.

As for the third choice, I’m all for it but I’ve been beaten to the punch by the superb work of Mr Larry Kaniut, whose fine two-volume series “Alaska Bear Tales” contains hundreds of first-person accounts from people who’ve been attacked by wild bears and survived long enough to be interviewed. Clearly, these people know what they’re talking about. Oh, well, except for the fellow quoted on the back cover: “As I felt those rough teeth pierce my skull, I was blinded by a single thought: ‘This is it; I’m going to die!’” I’m sure that every time someone throws that line back at him and then comments on his ongoing metabolism, he feels pretty sheepish.

And so, I’ll use what remains of this column to explain what you ought to be doing to prepare for any major Mac OS upgrade. It’s a terrific opportunity to adopt a scorched-earth policy regarding your hard drive and to start afresh. An OS is a living, breathing, and unnaturally complex organism. You’re familiar with the concept of your computer Working or Not Working, but there’s another state: Ailing. It’s been years since your OS was installed anew, and various system files have become corrupted in minor but critical ways. And the system directory has become choked with crumbs left behind by long-removed apps.

This faults can cause all kinds of problems ranging from the subtle to the wrath-of-God-like, and you’ll never work out what, exactly, is going wrong. So it’s good form to perform a clean “archive and Install” instead of having the Installer renovate what’s been there since 2001.

You’ll need lots of extra room to do an archive and install – the Installer moves your old OS to a separate directory and installs a brand new copy from scratch – so the other thing you need to start doing is removing all the useless clutter from your drive. You should be keeping about 10 per cent of your drive empty anyway, just to maximize your Mac’s performance, but it’s easy to slack up on the housekeeping.
Which actually brings up an even more dramatic suggestion: I like to actually reformat my whole drive once a year or so; it’s the ultimate housecleaning exercise. I’ve just done a count and discovered that I have 410 apps installed. If you offered me £5 for every one I can name, you’d get change back from a hundred. And I’m shocked to learn that 20 per cent of my hard drive is taken up by my iPhoto library. Those 120 five-megapixel images of my friend’s 2002 wedding outlasted the actual marriage; if Sylvia’s banished him from her heart, why haven’t I banished him from my PowerBook?
Naturally, the process begins with a complete and careful backup, which (unless you have a huge backup storage device) might take you a while. So, ha! If Tiger isn’t out when this column runs, it turns out that there’s a good point to it being published early after all! My very existence defines the parameters of law and sanity, and my pronouncements shouldn’t be questioned.

I reformat the drive with Disk Utility, which also gives me an opportunity to add partitions. Creating a five-gig partition allows me to install a complete, second copy of the OS, for example: if the main volume won’t boot for some reason, I can still start my PowerBook from the emergency partition. Then I install a brand-new OS and fresh copies of all of my critical apps (any of which could have become subtly-corrupted over time, just like the OS) and when the dust clears, I marvel at all of the extra elbow room. If in the coming weeks I actually start to miss a particular app or some particular files, I install them from my backup. But inevitably, after a brief breaking-in period, I don’t notice anything different at all. Except, of course, that my Mac now runs noticeably faster, and that I seem to have magically found an extra 20GB of free storage.

When Tiger does ship, you should go right ahead and start doing absolutely nothing. All software receives testing before it ships, and building a new OS is like building a new jetliner: its designers don’t send it up into the air until they’re sure that it won’t come crashing back down on their intended customers’ heads. Still, the last and most desperate bugs won’t be wrung out and fixed until the OS is in the hands of ordinary users, a species who can be counted on to do the most improbable things at the worst possible time.

Many of your brothers and sisters lined up at Apple Stores all across the planet, and had the new OS up and running on their PowerBooks minutes after midnight on the first day it shipped. But a sad subset of those people had it crashing and burning several minutes later. Let these people be your guinea pigs. Let them discover that when you use Tiger with a specific app and a specific printer, all of your documents come out peppered with random and ambitious profanities.

See, when they start posting their experiences to Macworld’s forums (www.macworld.co.uk/forums), you’ll read about those problems instead of living them. And if you followed my advice and bought the Bear Tales book, you already appreciate that there are some things in life that are best experienced vicariously. MW