“Oh sure, Mrs. Jones. You can purge the cache file after going online. That will make it appear like that web visit never happened. Here, I’ll show you.”

Ethan logged on to the National Geo graphic website, then exited and showed me the options for clearing the cache on the computer. I was crestfallen.

“So I can’t really track what the kids are doing at all, can I? I mean, if any of them figure out how to clear the cache—which is just a click away—then they can visit all sorts of places when I’m not looking and I’ll never figure it out.”

“Well you have the basic security functions,” Ethan tried to assure me.

“But they’re not foolproof either. You demonstrated that the first time we set them up. It seems to me I can’t really control where the students go or what they do. Maybe a teaching module on Internet navigation isn’t such a good idea.”

Ethan was thoughtful for a bit. He is a bright kid. Earnest, but lonely. I had the feeling his parents loved him but had no idea what to do with him. He is too smart, intimidating even for adults. The kind of kid who is meant to suffer for the first twenty years or so, but then would take his software company public at age twenty-one and wind up married to a supermodel and driving a Ferrari.

He wasn’t there yet, however, and I felt bad for his painful shyness, the way he regarded the whole world through this highly analytical lens the rest of us could never see.

“You understand that when you delete something on a computer, it never actually goes away?” he said presently.

I shook my head. “No, I don’t understand that at all.”

He brightened. “Oh, absolutely. See, computers are inherently lazy.”

“They are?”

“Sure. A computer’s primary function is to store data. If you think about it, the hard drive is nothing but a giant library lined with empty shelves. Then you, the user, come along and start inputting documents, or downloading information, or surfing the Internet, whatever. You’re creating ‘books’ of data, which the computer then stashes on the shelves.”

“Okay.”

“Like any library, the computer needs to be able to retrieve the books at a moment’s notice. So it creates a directory, its own version of a card catalogue system, which it can use to find each particular piece of data on the bookshelves. Got it?”

“Got it,” I assured him.