It's been a shakeout year for MS DOS word processing. Samna dropped Samna Word and sold Ami to Lotus. Software Publishing Corp. clipped `pfs:' from Professional Write and sold the rest of its low-end `pfs:' line to Symantec.

WordStar International quietly dropped Wordstar 2000 (but not klunky old WordStar) .Say goodbye to DisplayWrite and XyWrite. IBM's Displaywrite 5 package warns there's no support after June 1, 1992. Xyquest's latest XyWrite update, now called Signature, is to be sold mainly by IBM. But Xyquest will upgrade XyWrite users to Signature for about $100.

While old word processing programs for MS DOS are dropping like flies, new programs keep coming along that run under Microsoft's Windows. Recently we compared newcomer Legacy with Word for Windows and Ami. All three programs use Windows for Dynamic Data Exchange (DDE).

It's a new term worth remembering. DDE links selected data from several files, even files created by different programs. Updates to the linked file automatically update the file it's linking with.

Let's say we're writing a report in our word processing program. We'd love to include a chart from our spreadsheet program, but we know that by the time we get the report into final draft, we'll want the spreadsheet with next month's figures.

Using DDE to link that spreadsheet, the report's first draft will show this month's figures. When we print the final draft, it automatically shows the updated figures.

DDE seems so simple, yet brings enormous new power to computers.

As programs go through their next few revisions, watch for DDE in more and more Macintosh and IBM programs.

A couple years ago, Ami was an excellent desktop publisher - almost as talented as Ventura Publisher. You drew a "frame" around any space in a document. Into it you could put text such as blurbs and photo captions, draw in designs or move in artwork from clip-art and other programs.

Ami also borrowed Microsoft Word's inventive "stylesheet" approach. Ami came packed with 25 useful stylesheets set up and ready to use. You didn't need to be artistic to create a good-looking newsletter or report. All you had to do was select the stylesheet whose look you liked best. Conforming your copy to that style was a cinch.

But at the time we listed all the word processing features that were missing from Ami: thesaurus, four-function math, macros, footnotes, a double underline, index-generating ability and a setting for multibin paper feeders.

It's as if Samna tore out the column and passed it on to their programmers. The present version, Ami Professional, fills all the holes we mentioned except for multibin paper feed. It also has a tablemaker that works just like a spreadsheet.

It creates pie, bar and other charts from whatever data you give it. If you're moving from a Mac to the IBM world, you'll feel right at home with its PPP design (pull-down and pop-up menus and point-and-click dialogue boxes).

It costs $300 more than it used to, a hefty $495 from Lotus, its new owner. There's no pleasant way to use it without a mouse. If you like mousing and you're into IBM-compatible desktop publishing, Ami Professional is worth a hard look.

So is new Legacy, by NBI, an old manufacturer of dedicated word processors. It borrows Ami's "frame" idea. You can put a frame anywhere in a document and put anything inside - text, photos, spreadsheets (with formulas) - from the same file or even another program's files.

Legacy's version 1.1 is already a good across-the-board word processor and desktop publisher. Searching and replacing is very flexible. So is the tablemaker, which can subdivide columns and rows. Legacy has both a standard and a scientific calculator.

It comes with three helpful manuals, including one on design. It supports a wide range of printer fonts. But it doesn't yet run well on networks. Its help screens don't help you in dialogue boxes. It doesn't make macros yet. The dictionary has some incorrect definitions. And arrows mislead you into trying to type while the program is tied up working.

The worst problem is an unrecoverable disk error that dumps you unceremoniously from the program every once in a while. But the next version should correct all that.

Word for Windows combines the best in Ami and Legacy when it comes to word processing and document handling. That's no surprise, since Microsoft designed it while working on Windows.

It word-wraps in columns and does red-lining, a very useful feature for writers working with editors or other writers. In printing, it can select paper from a three-bin feeder. It draws lines and boxes easily and flexibly. It's great for offices that have Macs and IBMs, since it works exactly like the same program's Macintosh ver-sion.

It's not quite as fancy or flexible a desktop publisher as Ami or Legacy. But for most offices, it's more than adequate.

Differences between these programs are mostly a matter of taste. All Windows word processing programs are slow, since they run in graphics mode, repainting the screen every time you page up or down.

Don't install one on a computer that has less than 386sx power and 2M RAM. The programs use a lot of disk space. (So does Windows.) If you intend to use DTP features, reserve at least 20M on your disk.

All three programs sell for $495 and are available through local computer stores. They all convert files to and from all the popular IBM word processors. Ami is also available for Hewlett-Packard's New Wave.