Q: I have a 10-year-old and want to find out about software to teach him programming.

A: Programming a computer involves intense concentration that few adults, let alone children, have.

But if you want to proceed, you can introduce children to this discipline through what's known as turtle geometry. Conceived by researchers at Massachusetts Institute of Technology, it today underlies a computer programming language called Logo.

In Logo, children can key in commands to move a turtle around a screen to create shapes, designs and graphics. Basically, the idea is to show how a well-crafted string of commands can result in a particular image or set of motions. Jim Muller's book "The Great Logo Adventure: Discovering Logo on and off the Computer" ($19.95), gives a good description of how turtle geometry works. You can go to the Logo Foundation's Web site (el.www.media.mit.edu/logo-foundation) to learn more.

Kids should get a wide range of experiences, possibly including programming. Personally, I would rather have my 10-year-old son make the throw to second base than learn how to write a go-to loop in Logo.

Q: My Mac G3 has a 17-inch display, and it has some strange fine lines in it.

A: If they are fine horizontal lines, don't worry--lots of G3 monitors do, and there doesn't seem to be much you can do about it. If the lines are vertical, keep on reading for exciting details.

It could be that you've got a problem with the software driver for your video card. The setup CD that came your machine didn't necessarily have the newest software. Go to the card manufacturer's Web site for the latest and greatest driver, whether Mac or Windows. This could be a quick and dirty solution.

If new software doesn't solve the problem, it is time to start swapping. Put a new video card in your machine and look for the funny lines; if they are gone, you have a video-card problem. If that doesn't work, put your monitor on another machine and see if the problem persists. If it does, you have a monitor problem and can contact the manufacturer about a replacement.

Q: I bought a used computer with a Colorado tape drive in it, and I am having trouble getting it to work. What advice can you offer?

A: I have certainly ranted and raved over the years about the need to make backups of data. The classic way is to install a tape drive. In theory, this works great. Reality sets in when you have a disaster and have to actually recover data from your tape.

If your dictionary were to list 10 adjectives to describe tape drives, the only printable one would be the word "cantankerous." As a general rule, tape drives can be controlled only through complex software. And tape is not a random-access medium, meaning you can't jump instantly to the material you want to recover; you have to let the tape run till it gets there.

And I would like to have a dollar for every system administrator who has suffered a crashed hard drive and reached for the tape backup only to find out that the tape is damaged. If not damaged, it can tear in the middle of the backup.

So my advice is: Forget about that Colorado tape drive. Hard drives are cheap--install a secondary drive on your machine for backups. Or you can use a Zip drive. If you feel technically inclined, burn a "CD-R" disc for backup.

Use tape only if you have the number for a suicide hot line written next to your phone.

John Gilroy of Item Inc. is heard on WAMU-FM radio's "The Computer Guys" at 1 p.m. on the first Tuesday of the month. Send your questions to him in care of The Washington Post, 1150 15th St. NW, Washington, D.C. 20071-5302 or via e-mail at jgilroy@iteminc.com.