Today I’d like to introduce a new series of articles we’re calling FlippedBITS. Our premise is that technology breeds misconceptions, and far too often, due to a lack of information, we develop mental models of the way things work that are plausible — but wrong. Those mistaken ideas, in turn, make it more difficult to solve everyday problems and can lead us to waste time, effort, and money. In each installment of FlippedBITS, I’ll examine one or more of these misconceptions and do my best to set the record straight.
My 2-year-old son is still learning the basics of how the world works, and it’s fascinating to watch his understanding of technology evolve. Just a few months ago, he’d pick up a remote control and try to talk on it like a telephone. In his mind, any oblong plastic box with buttons on one side must be a telephone — it’s easy to see how he might make that mistake. (And, in all fairness, we had a telephone and a remote control that looked mighty similar to each other.) Now he understands that a remote control is different — it’s the thing we point at the TV to make it play his favorite shows. But then he became confused and frustrated when we handed him a toy remote control that only made noise when he pressed the buttons; he
couldn’t understand why the TV wouldn’t respond.
We expect kids to make these kinds of errors, and we laugh knowingly as we watch how they try to put something into one logical category, notice that it doesn’t quite fit, and then try another. This is all part of growing up. But in fact, we never stop trying to make sense of the world. We encounter a new thing we don’t entirely understand, and we automatically — perhaps unconsciously — start trying to construct a mental model of what must be happening behind the scenes. These models not only help us explain what we’re seeing, they help us predict how things will work in the future. It’s just that sometimes, through no fault of our own, we guess wrong.
For example, I remember the first time I heard of this newfangled device called a “laser printer.” I was a freshman in college. I got that paper went in blank and that, due to something involving a laser, it came out with crisp black text. But the initial idea I had about how this worked was that the laser was somehow burning the letters directly on the paper, because after all, burning is what lasers do. Later, when I found out that laser printers used a black powder called toner, I had to revise my theory. Maybe the paper was covered with toner before the laser zapped it, and the heat from the laser caused the toner to melt in spots and stick to the paper. That turned out to be wildly wrong too, of course. I had no idea at the
time that a laser beam could reverse an electrostatic charge that otherwise causes toner to stick to a drum, that when paper rolled along that drum, it picked up the remaining toner (again, due to electrostatic attraction), and that a combination of heat and pressure then fused the toner to the paper. My theories had seemed reasonable based on the available information; they even correctly predicted that the paper would come out of the printer warm. But my mental model didn’t happen to reflect reality.
Misconstruing how a laser printer worked had no negative consequences for me. But sometimes erroneous mental models lead to serious problems. If your mental model of how a car’s air bags work is that they offer complete protection in any sort of crash, that could lead you not to bother wearing a seatbelt, which might prove deadly if, for example, your car flipped over.
I get lots of technical questions from people who have read my books and articles or heard me speak somewhere. A fair percentage of the time, the questions are phrased in a way that shows they come from a mistaken mental model. For example, in the last several weeks at least three different people have asked approximately the same question: “Since FileVault encrypts all the files on my disk, doesn’t that mean when I copy a file to another disk, it’s still encrypted?” No! It absolutely does not mean that. (I’ll explain why in a future FlippedBITS article.) But I can easily see how someone might draw such a conclusion — and misunderstanding something like that could cause someone to make an unsafe decision about how to handle
I’ll admit it: When I hear questions like this, I sometimes have to fight the temptation to roll my eyes and say, “What an idiotic idea!” But I’ve had (and probably still have) plenty of idiotic misconceptions myself. Not understanding something, or having a faulty conception of how it works, doesn’t make you stupid. It only means you haven’t yet acquired enough information about something. I’ll do my best to supply those missing facts and put us all on the right path. I already have a healthy list of prospective FlippedBITS topics, but if there’s a topic you think might be an appropriate fit, please feel free to suggest it.
So, whence the name “FlippedBITS”? Apart from the fact that we at TidBITS like to append “BITS” to everything, we thought that flipped bits would be an apt description of the kind of error we’re trying to correct. Computers, as you know, store information as a series of ones and zeroes. Every “slot” that can hold either a one or a zero is a bit. If the bit’s value is zero and you flip it, it becomes a one. Flip it again, it’s back to zero. Sometimes bits get flipped inadvertently due to programming errors, mechanical failures, media degradation, cosmic rays — really! — or other random occurrences. And unfortunately, a single flipped bit — a one where a zero should be, or vice-versa — can mean the difference
between a program succeeding and failing. After all, 01110111 is “w” in binary, but 01110011 — almost the same, but with one bit flipped — is “s.” Sometimes a change as small as a single flipped bit can spell the difference between a “win” and a “sin”!
With that, allow me to direct you to the first article in what I hope will be a long and helpful series: “FlippedBITS: Booting Your Mac from a Duplicate” (13 March 2013)