I’m : a programmer, writer, podcaster, geek, and coffee enthusiast.

Do you have a computer?

Do you care about any of the files you’ve ever saved? Music you’ve bought from iTunes? Documents you’ve written? Pictures you’ve taken?

At some point, you’re going to see this icon flashing when you turn on your Mac. (I don’t know what Windows PCs do these days for this. Probably a BIOS message about not finding a boot volume.)

This icon means: My hard drive is dead.

(Usually. It literally means that it can’t find a bootable hard drive. But hard-drive death is by far the most common cause of this symptom.)

I get emails from friends about once a month asking what this means, quickly followed by a sinking feeling that I need to tell you this, and you almost definitely don’t have a backup of anything, and you’re going to ask me about data recovery, and I’m going to need to tell you that it doesn’t usually work, and you’ve probably lost the photos from your great European vacation or your baby’s first steps or the last four years of your life.

Here’s a quick primer on the reality of hard drives:

The only way to secure your data is to back it up.

I cannot stress this enough: BACK UP YOUR DATA.

If you’re on Windows, search MSN Bob Live Bing or whatever it’s called this month and figure out how to back stuff up. It will probably involve a lot of dialogs, information balloons, wizards, and explanatory text all over a translucent interface with an overuse of pastels.

If you’re on a Mac and you have OS X 10.5 or better (check: is the Apple icon in the upper-left gray?), it’s a lot easier. Here’s how it goes:

  1. Buy an external hard drive that’s bigger than your computer’s built-in hard drive. These hardly cost anything these days. Seagate and Western Digital are great brands. Look, here’s a terabyte. Want to save desk space and power cords? Here, a compact 500 GB disk. Lowest cost possible? A full-sized 500 GB disk.
  2. Plug it into your computer. It will ask if you’d like to use this drive for Time Machine. Say yes.
  3. Whenever your computer is at your desk, leave the external drive plugged into it and turned on.

That’s it.

A quick note about external drives: Many laptop owners buy external drives for extra space because they fill up their main drives. That’s nice, but that’s not a backup because those files still only exist on one hard drive (the external), and any hard drive (including externals) can die at any time. You should have an external drive dedicated exclusively to backup, and that’s exactly what Time Machine does.

We know, collectively, as geeks, we’ve let you down with backup procedures in the past. They’ve been tedious and easily forgotten. But OS X’s Time Machine is so easy and automatic, and external drives are so big and cheap, that there’s no excuse anymore.

Nearly everyone has lost data because it wasn’t backed up. It happens to the best of us. But it should only happen once.