Okay so the cat is on its way, time to put some planning into action - hey, it'll give the TNT site a break from my continually checking where it is.

Upgrading Mac OS X can be typically done one of three ways, direct update (in place upgrade), Archive and Install (backup system files, retain user documents, network settings etc.) or Erase and Install which is exactly what it says. At each major OS upgrade I've used the opportunity to clear out the cobwebs and do an erase and install. This means there are no dodgy kernel extensions, input managers and the like hanging around. Archive and install would achieve the same, but the directory and file system would still be fragmented. So, to backups.

Backup Rule 1a: you can never have too many backups.
Backup Rule 1b: never trust your data to fewer than three different sets of media.

Kathy & I typically have three or four different backup sets on the go each. Daily (different location, same disk), Weekly, external drive and an old 4Gen iPod which is then stored in a safe at an Undisclosed Location. Also, occasional DVD burns of same, and very occasional backups of big stuff like pictures, iTunes libraries to an external HD. Each backup set has at least a couple dozen instances. Retrospect makes all this so seamless you almost don't realise it's going on. All I need to remember is to plug in the external drive before starting our own version of Iron Chef on Saturdays.

Backup Rule 2: test your backups.

What point is all this backing up if you can't get anything back? Regularly test that you can actually retrieve files and folders from your backups (and that the files are readable.) Here's an interesting one; I don't know if Retrospect actually runs under Leopard [update: it does], so while it's good insurance to have (Kathy's going to hang back on 10.4 for a while) I'm going to go with a more native approach and use Mike Bombich's excellent Carbon Copy Cloner. This clever piece of work can do a full bootable clone to another hard disk, but it can also backup to a disk image which is what I'll be doing since I know Leopard will read these.

Backup Rule 3: backup your configuration as well as your data.

Network settings, keychains, what applications you have installed, da woiks. All these play a vital part in getting going after a fresh build. What's the point in having a shiny new OS if you can't get your Mac onto your airport network? And without a list of installed apps, it can take you weeks of adding "just one more thing" to get the full collection of tools back together again. Luckily one of Apple's own tools helps out with this: Apple System Profiler. This critter not only gives you a full inventory of your apps, it also notes every network detail of every network location, except passwords. Those you'll need to track yourself using either Keychain or a password manager (my tool of choice is Web Confidential. Years old, but dependable.) Use System Profiler to save a complete profile to your backup disk.

If you have an Apple ID (if you've shopped at Apple online or iTunes Music Store you have one) it's handy to note it and your password down on paper, as well as your current airport network password (if applicable.) This will help fill out a lot of account information when the install is complete (even if you don't feel like registering.)

After all this, we're about ready to go... except I checked with our mail room and TNT have been and gone so it looks like my copy of Leopard isn't going to arrive until Monday.

<sigh>

But hey, at least I'm ready for it. In a cat-like state of readiness, in fact.