When it becomes timely to make predictions about the coming year, a decent respect for the opinions of readers requires that columnists declare how well they did with last year's predictions.

Our predictions for the personal computer world in 1990 were right on point -- up to a point. We did say 12 months ago that a new version of Windows would come out. But we had no idea that Windows 3.0 would sell 1.4 million copies and create a new de facto standard for DOS software, all by the end of the year.

We said that Apple finally would produce its new, lower-cost models of the Macintosh. But we had no idea that the most important of the new Macs -- the LC, offering a color system for about $2,000 -- would be put off until 1991. The delay occurred because Apple Inc. Chairman John Sculley decided late in the design cycle to upgrade the LC's display quality. The chief omission in last year's predictions was our failure to guess that IBM would bring out a low-cost family computer, the PS/1. Given the tepid sales figures so far for this easy-to-use but underpowered machine, IBM may wish it had omitted the PS/1 as well.

One of our chief screwups was a familiar mistake for this column. Once again, we predicted that the Unix operating system would start to play a big role in the PC world. Once again, we were wrong. We never, never will make such a prediction about Unix again (at least until next time).

Looking to 1991, we can safely predict that one of the hot new buzzwords in the personal computer business will be "software." No, not that software. Not the programs that you buy on a floppy disk and load into your PC. We're talking about the expanded version of "software," referring to information in just about any form.

For example, when Japanese hardware giant Matsushita recently bought the American movie-and-music giant MCA, all the media analysts said the buyer was interested in MCA's "software." This doesn't mean that MCA will come out with a nifty new spreadsheet. It means that Matsushita was buying the tapes and disks that contain MCA's movies, TV shows, records, etc. That stuff -- any information or entertainment that you access through a hardware device -- is known as "software."

The reason this definition of "software" becomes important in the PC sense is because of another hot buzzword for 1991: "multimedia." This year should see a big expansion of systems using the concept of multimedia -- that is, a personal computer that controls a videotape display, an audio CD player, or a CD-ROM drive that acts like a massive, fast-access hard disk.

Another hot term that may become important in 1991 is the phrase "non- keyboard." This refers to various methods of putting information into a computer other than through a keyboard. The concept is getting a lot of emphasis because advancing technology now makes it possible to build a complete PC in a package about one-third the size of a standard keyboard. Since increasing the size of these "palm-top" computers to accommodate a keyboard would defeat the purpose, there is a lot of work in progress to find other ways to load information into a machine.

Watch for new "stylus" type small computers. With these, you take a pen-shaped electronic gizmo, the stylus, and write on a special slate. The stylus device translates your handwriting into ASCII code and sends it on to the computer. Such systems already are in use for special applications such as warehouse inventory. In 1991, you should see various non-keyboard programs on the market that allow you to load handwritten data into spreadsheets, database managers and personal appointment software on standard PCs.

Another keyword for 1991 will be "data conversion." As noted here before, the PC world is moving toward a single-standard interface. But we're not there yet. So there will be more and more software making it easy for you to convert data from a DOS-type format to a Mac or (Japanese standard) NEC or other operating systems.

That's fortunate. After all, you're going to need data-conversion capability to move programs from your current computer onto a bigger PC or workstation running Unix. Because 1991 is the year when Unix is going to start playing an important role in the world of small computers. You read it here first.T.R. Reid is a Washington Post foreign correspondent. Brit Hume, a contributor to the Washington Post Writers Group, is chief ABC News White House correspondent and the founding editor of a computer newsletter.