Last week my G5 iMac started to act funny, and then it crashed. And it crashed not in the friendly way apple computers are supposed to crash, with a box that says we're sorry about this, please restart your computer; not even the frozen screen or the spinning rainbow cursor from hell; this crash made me jump as though two hands had come out of my screen reaching for my neck.

Those of us who grew up on a mouse and keyboard interact with our computer the way we interact with a stack of books on our desk, or a refrigerator, or a bicycle. When I double-click on a folder of halloween pictures, my brain treats the act of opening the folder and the contents of the folder no differently than a physical photo album sitting on my bookshelf. This is exactly the point of a point-and-click interface, it feels like real life, but physical photo albums don't crash, and the conflation of the real and the digital represents an illusion that vanishes when on top of my pretty digital desktop appears a smattering of uninvited, primitive computer-text that starts with SYSTEM FAILURE.

My mother never let computers dupe her in this way. To my mother computers are mysterious, fragile, not to be trusted. When she is presented with digital information, her instinct is to bring it out of the computer and into real life. I do exactly the opposite. I recently acquired a boxful of family photos, and my reaction was that they were too precious to stay in the box or even to frame and mount on my wall, as my apartment is susceptible to earthquake, fire, flood, and theft - I had to secure these photos for all eternity by posting them on Flickr. Posting them on Flickr? Talk about being duped. Flickr could tomorrow disappear off the face of the earth, they could without warning start charging a zillion bucks a month, they could sell my pictures to North Korea. What's more likely to be around in twenty years, the bar mitzvah photo album that lives under the coffee table in my dad's Philadelphia living room or Flickr? How silly. When I got my computer to the repair shop, the technician opened her up and showed me logic board stir-fry. Thank god for extended warranty.

The appropriate way to deal with the illusion of data as real, and not the invisible stream of particle-switches that it is, is to create redundancy. The more it matters, the more redundancy you need. I recently toured a medical helicopter that had two completely separate engines, only one of which is used at a time. Think of your computer workspace not in terms of what you would do if it crashed, but in terms of how to minimize the inconvenience when it crashes. My mom prints out emails I send her and saves them in a folder in her