WRITTEN BY STEVE JOHNSTON ILLUSTRATED BY PAUL SCHMID

As most parents know, teenagers know everything there is to know about everything there is to know. Even when the teenagers don't know diddly-squat about the subjects, they would never admit it. Instead they pretend to have insider knowledge by rolling their eyeballs to the back of their skulls when you ask them about something.

But I have to give the Johnston children credit for one thing. They know computers. And I don't mean just how to turn them on. They actually understand how to make computers do more than act like fancy-pants typewriters with television screens attached.

When something goes wrong with my computer, I have to ask a Johnston child for help in getting it fixed. It's usually something simple, like making the computer cough up a story or getting it to connect me to someplace.

Before asking for help, though, I like to fool around with the computer for several minutes and really screw things up. Then, I am ready to call in a Johnston child. The child will help, but there will be long sighs and more rolling eyeballs as the child repairs the damage, fingers moving on the keyboard as fast as Superman on speed.

Soon, the child will look at me with profound pity and say, "There. That was simple."

I am too ashamed to ask what the child did to fix the problem. Besides, I wouldn't understand what I was told anyway. It would be like explaining to a caveman how the TV remote works.

(I must digress. I wasn't born in the Dark Ages. I am an old baby boomer, but when I start telling my kids about "how things were when I was growing up," you would think I came across the country in a covered wagon and helped Tom Edison invent the light bulb.

(The other day, a Johnston child got a telephone. It was small — about the size of a deck of cards — and it had its own number. You could slip it into your pocket. And amazingly, it places calls from anywhere in the world. Plus, it takes pictures that you can send to someone with a computer. On top of that, instead of ringing like a regular phone, it plays tunes the kid likes to hear.

(I told him when I was a kid our family had a phone that was on a party line. Having a party line meant you shared telephone service with a half dozen other families. You could tell whom the call was for by the phone ring. Three short rings were for one family, and a long and a short ring were for another family. Of course, everyone listened in when your neighbor got on the line.

(The child really started to roll his eyeballs when I told him about going to San Francisco in 1979 and using one of the first computers to send stories back to Seattle. When the phone operator heard the static sound of the computer in Seattle answering the computer in San Francisco, the operator would hang up, saying there was a bad connection. I had to explain that it was one computer saying it was ready to talk to my computer.

(If the child makes the mistake of pretending to listen to me, then I tell about the first electronic game I ever bought. It was called Pong, and it was an electronic ball bouncing inside the television set. You twisted knobs on a hand control to get the paddles to move up and down to hit the ball.

(Snapping out of the coma, the child would ask, "And ???"

("And nothing," I would say. "That was the game. You hit the electronic ball to the other side. We could play for hours."

(That's enough digressing. This kind of talk makes my kids sleepy, and drool starts running down their cheeks.)

At the rate things change, I can't wait until my children have teenagers of their own (I believe they are called grandchildren) and they ask their kids for help with the computer.

"Are you still using that old thing?" the future child will ask. "Why don't you get a computer implanted in your brain like everyone else? You are so-o-o-o old-fashioned."