In earlier times, migrating to a new Mac wasn't too hard. Just copy some files over. Today, however, the upgrade isn't exactly like dustin' crops, as Han Solo might point out. Here are some procedures that will make the upgrade trouble free and painless.

Step #1: Preserving Your Data

The first thing to remember is that there are two kinds of backups. The first is a static backup such as, in the case of a Mac, a Finder copy to an external drive. Specifically, I'm talking about copying /Users and /Applications. Every time you do that, you create a static snapshot of your principle data on the Mac's hard disk.  However, if you want to go back in time to recover a deleted file from eight weeks ago, static backups can't provide for that.

Apple's Time Capsule

Apple's Time Machine (TM) on an external drive or the dedicated Time Capsule product can provide the dynamic backup needed to go back in time from the epoch of the first total backup. Sometimes, however, it's more convenient and faster to have a Finder copy backup as well, and having both kinds of backups is probably a good idea, especially of there are any minor problems with the TM archive.

Finally, backups don't provide real redundancy if they're all in the same room. If there's a flood or a fire, you could lose all your backups. That's where an offsite backup comes in. It could be something you do online, like Mozy.com, or it could be something like a Finder copy backup to an external drive that's stored in, say, a safety deposit box or a relative's house.

Just remember this: the best possible way to back up a hard disk is with another hard disk. Not Blu-Ray discs. Not tape. Not DVDs.

I bring all this up because the first step in migrating to a new Mac is ensuring that, if something goes really wrong -- or you make a mistake during the migration -- your important data remains safe. This is a bigger task now because, unlike just a few years ago when a family only had a few hundred megabytes of correspondence and tax returns, the typical family of 2009 may have nearly a terabyte to work with. So, in effect, you need to be your family's IT manager and prepare in advance before buying a new Mac.

The bottom line: when you think about buying a new, bigger, faster Mac, also think about having all the data on the old Mac safely backed up. This project can take hours. Just do it.

Step #2: The Actual Migration

It can take a long time to duplicate the settings, licenses, and other customization you've carefully built up on your old Mac. Perhaps the simplest way to ensure that your new Mac works just like your old one is to have a current Time Machine backup of the old Mac on a fast external drive just before you start the migration process. (There are other ways as well, but I'll keep it simple here.)

In my case, I made one final TM backup, then disconnected the old Mac from my network to make sure nothing much changed. Then I disconnected the FireWire 800 drive with the TM backup from the old Mac and connected it to the new one and then booted it up.

It's a really good idea to do the transfer this way because if you don't, and elect to use Apple's Migration Assistant later, you might lapse and let the new Mac, with a new admin account, diverge from the old Mac. Then you're faced with file re-integration issues.

As an aside, here are two important notes.

• When you boot up the new Mac, you're asked to create an admin user name. DO NOT use the primary admin name you had on the old Mac. Specify a new admin account, like "admin2" with a good password. You always want to have a second admin account anyway. Then when TM brings in your old data, it'll install it all under the user name you had on the old Mac, unmodified -- plus the other accounts you may have had. If you don't do this, TM will force you to rename the old account name, something you may not want to do. Fixing such a snafu could require some UNIXy techniques, best handled by a command line expert.
• This is where FireWire 800 pays off. If you've been using USB2 for casual external drive backups, you'll pay a price at migration time. FireWire 800 is significantly faster than USB2. The motivation here is that boredom and frustration during this critical time leads to shortcuts and mistakes you'll regret later. FireWire 800's speed (about a gigabyte/minute) will help eliminate that.

Migration Assistant is in /Applications/Utilities

The next thing to do, after Migration Assistant is done, is to let the old Mac run, side by side with the new one for a few days. Don't be too eager to sell it or toss it. Do lots of spot checks to make sure important files came across and are readable and not corrupted. One trick is to use QuickLook. Give yourself lots of warm fuzzies on this. If the new Mac's hard drive turns out to be defective, which can happen, you'll have plenty of time to get the new Mac fixed under warranty, then restart the process. During this time, your old Mac remains a valuable backup resource.

Don't worry too much about comparing file sizes in the Library because, it appears, TM doesn't try to restore old caches. On the other hand, comparing file sizes for some sampled personal files is another good check.

In Part II, I'll talk about clean up operations, multiple drives on the old Mac, and preparing that old Mac for sale, (including Mac OS X licensing) or disposal.