FOR years the ritual was the same. Supporters of the Unix operating system would proclaim that their time had come - that widespread acceptance of Unix was at hand. But 12 months later, Unix would remain right where it had been, firmly entrenched in the academic and scientific computing centers and largely ignored by businesses. With all its strengths, its supporters would say, all Unix lacked was momentum, a bandwagon effect that would drive it through the business world.
Now Unix finally has momentum, but its supporters are so busy bickering and preparing for a civil war that ''the Year of Unix'' might slip away once again. Just possibly, though, a stronger Unix may emerge.
Unix was developed by the American Telephone and Telegraph Company, which had the idea of creating a single operating system that would run across the full range of computers, from PC's to Cray supercomputers. This would give it a huge industrywide advantage over the operating systems for Apple computers or those compatible with machines from the International Business Machines Corporation. Yet for a long time, A.T.& T. found little support for the cross-vendor concept, in part because companies generally bought all their hardware from one vendor and used the software provided or recommended by that vendor. Over the years Unix captured a base of about 600,000 users, while the Microsoft Corporation's Disk Operating System, widely known as DOS, built a base of at least 12 million.
Why was the going so slow for Unix? To the computer user familiar with such PC operating systems as DOS, OS/2 and Mac OS, Unix can be very hard to use. To bend a phrase, it is user-unfriendly, even user-belligerent.
Unix also comes in many flavors. A.T.& T. has licensed Unix widely, and many companies have concocted their own versions. I.B.M. has AIX, for example, which it introduced to seek a place in the scientific and engineering market. Apple has A/UX for the Macintosh II. Microsoft has Xenix. There's also a variant called Berkeley Software Distribution (BSD).
Why is Unix picking up momentum now? There are several factors:
* The rise of distributed network computing, in which the traditional hierarchical structure of business computing - PC's, minicomputers and mainframes - is giving way to a system of computers consisting of servers, or data storage centers, and work stations. Unix can provide access to all facets of the computer network, in a way that other operating systems cannot.
* The increasing power of software developers who wish to conserve resources by writing programs for one system instead of many. Programmers say Unix provides a sophisticated environment in which to write new software. And instead of rewriting the same code 23 different ways, they could more productively write it once and then spend their time improving it. This could also lead to the creation of more software applications, which Unix needs.
* The growing acceptance of Unix among Government computer buyers, who are so impressed by Unix's ability to cut across brand-name lines that they are willing to put up with its complexity.
* The reluctance of businesses these days to buy computers and software exclusively from one supplier. The day of the all-I.B.M. shop is over. Today's offices are likely to embrace hardware and software from many vendors, and the idea of a single operating system that will work with all of them is appealing.
* The confusion surrounding I.B.M.'s OS/2 operating system. I.B.M. did a superb job last year of extolling the virtues of OS/2, explaining, for example, why multitasking systems make sense for businesses. (They allow a user to work on several different applications at once, which cannot be done under DOS.) The trouble is that OS/2 was not available when I.B.M. was touting it; Unix, which does everything OS/2 can do, was.
* The agreement last year between A.T.&T. and Microsoft, the biggest maker of software for PC's, to merge Unix and Xenix into Unix System V Version 3.0. Perhaps more than any other factor, this revived interest in Unix.
