The spreadsheet wars are coming, and one of the major weapons in that multimillion-dollar commercial struggle will be a concept that is emerging as the hottest new buzz-phrase in the personal computer software: "soft interface."

It has been five years since the programming geniuses at Lotus launched the impressive new spreadsheet known as 1-2-3. Since then, other software houses have watched in envy as 1-2-3 sold more than two million copies, becoming the most successful program in PC history.

As Adam Smith observed 200 years ago, market success spawns market imitation. But none of the countless 1-2-3 imitators has made much of a dent.

In an industry where few programs last more than two years without major alterations, the five-year-old Lotus offering still has about 65 percent of the huge MS-DOS spreadsheet market, according to industry analysts. Lotus stumbled when it tried to expand its hegemony to the Macintosh world.

Jazz, the Lotus spreadsheet for the Mac, is a weak sister -- both in performance and in sales -- compared to the marvelous offering from Microsoft called Excel.

But in the spreadsheet game, the Macintosh market is not quite the big leagues. Total sales of all Macintosh spreadsheet programs come to about 180,000 per year; a company could sell more than that with just 15 percent of the MS-DOS spreadsheet market.

Attracted by those numbers, two other shining stars of the software galaxy are bringing out spreadsheets for the IBM-PC and other MS-DOS or OS/2 computers.

Microsoft has just introduced an IBM-PC version of Excel, complete with many of the handy features that make this spreadsheet such a joy to use on the Macintosh. While the new Excel reportedly can handle files and data from 1-2-3 spreadsheets -- and crunches numbers even faster than 1-2-3, according to Microsoft -- it offers the same friendly set of menus and the appealing range of type styles, graphics and printing capabilities found on the Macintosh Excel.

Excel is clearly aimed at the high end of the MS-DOS market. It costs $495 at retail (same as Lotus) and it only runs on the heavyweight machines with an 80286 microchip (like the IBM PC-AT) or an 80386 chip (like IBM's new Model 80).

In the middle price range, there's another new Lotus competitor from the industry's most ambitious up-and-comer, Borland. Borland's $195 spreadsheet is called Quattro (the name comes from the first line of the rock classic "Louie Louie").

I haven't had a chance to test drive it yet, but Borland says it handles 1-2-3 files, matches 1-2-3 functions, and also permits graphics wonders that the Lotus offering cannot achieve.

Lotus, believing that turnabout is fair play, has announced that it will fight back on Microsoft's spreadsheet turf. Sometime next year Lotus will bring out a new Macintosh spreadsheet, Modern Jazz, designed to cut into the huge lead Excel has in the Mac market.

But the key spreadsheet battleground will be in the IBM-PC market. And a key element of that skirmish will be a concept of software design that you ought to know about because it's all the rage among program publishers.

It's called "soft interface." That may sound like computerese for getting a pillow in the nose, but it actually refers to the language a software user employs to talk to a particular program. That is, the "interface" consists of the screen displays, the program's directory of commands, etc.

In ancient times -- in the personal computer world, this means any time before 1986 or so -- all software came with a "hard interface." That meant the program's author had established a set of commands, and the user had no choice but to learn them.

It might not have seemed particularly intuitive for a WordStar user to type the key combinations CNTRL-K-B and CNTRL-K-K to mark a block of text, but if you didn't memorize such arcana you couldn't use WordStar.

"Soft interface" turns things around. The new "soft" programs -- notably Excel and Quattro -- come with a command language of their own.

But if the users don't like any of the commands the program author created, they can make up a command set of their own. Thereafter, the program and its various Help screens will all reflect the new, personalized "interface."

This approach is designed to reconcile power with friendliness. To compete with 1-2-3, the new spreadsheets have to offer literally hundreds of different commands, functions, bells and whistles.

But how is any user going to master the labyrinthine complexities of these feature-laden program? The answer, or at least an answer, is "soft interface." It's hot and it's trendy. Watch for it in a program coming to your computer soon.endqua