There are well over 200 different personal computers being sold today, a little tidbit that's just dandy to know if you enjoy hearing about booming new industries. But if you're a consumer, it's got to be pretty scary, because a circumstance like that makes it virtually impossible for you to test--or even do research on--every make and model to find the one best suited to your needs.

And at up to $5,000 and more a pop, who can afford a mistake?

But that doesn't mean you have to throw your hands up in despair. There are a number of books that review most of the more popular models, so you can hustle down to your local bookstore and peruse those.

But while you're there, you might ask if the store also happens to carry the "Software Directory," published by PC Clearinghouse (which is based in Fairfax).

A software directory? Yes. And it's a pretty logical thing to consider.

Software is the stuff that equips a computer to do its work. It's the program that is written to transform the raw hunk of metal, silicon and wire into a desktop ledger or a check balancer or an electronic typewriter commonly called a word processor.

The problem is that most computers are able to use only software written specifically for them. So, just as an oil filter that might work in a VW won't in a Ford, a tax preparation package written for an Apple II Plus won't run on an IBM PC.

So, if you want to cover all bets, and your choice comes down to between two or three computers, it might behoove you to consider how much software is available to run on each of your candidates. That way, if you don't like the software you buy initially, you won't find yourself stuck because there's nothing else available for the machine to make it do what you need done.

The "Software Directory" isn't cheap--$29.95 is the cover price. And, in fact, it may not even be something you need to buy if your needs are limited. But it's worth a glance. If the book store doesn't have one, you might check your library or ask the sales personnel at your favorite computer store if they have a copy (and tell them they should if they don't).

The directory lists 21,042 "software applications"--which means pretty much the same thing as software without the qualifier--and cross references them with more than 200 computers.

You can look up your particular interest, anything from "Accounting (accounts payable)" to "Window Ad/Creation" and "Wirewrap Board Layout" (whatever that is). In between are word processing packages, Ham radio assistance packages, grocery store aids--in fact, it's just about a "you name it, we got it" situation.

Within each category is a listing of those computers that have software written for them to do those tasks. And under each listed computer is a listing of all the software for that category written for it.

Use the directory with a grain of salt, however. Not all software is included. Indeed, one of the most raved-about new personal computers, the new Epson, isn't listed either. Not hard to understand why, however, since so much new software and hardware is coming into the marketplace each week.

With that in mind, however, I thought you'd be interested in knowing what, according to the directory, are the Top 10 computer companies in terms of the amount of software written for their machines:

1. Apple Computer: 2,201

2. Radio Shack: 2,142

3. IBM: 1,488

4. North Star: 569

5. Commodore: 496

6. Heath: 359

7. DEC: 351

8. Atari: 339

9. Texas Instruments: 272

10. Cromemco: 206