IBM and Microsoft Corp. have begun spending millions of dollars on everything from television advertising to telephone support lines in an effort to woo personal computer owners to their competing operating systems: IBM's OS/2 2.0 and Microsoft's Windows 3.1.
But that flurry of marketing hype and salesmanship is just a preliminary round before the main bout: the battle over who will control the crucial market for operating systems on powerful "servers" that are increasingly displacing large computers.
Both OS/2 2.0 and Windows NT, an updated version due out late this year, will vie for a place in controlling servers, the central machines of computer networks. Unlike the battle for desk-top dominance, however, they won't be alone. At least three other operating systems, the core software that makes computers function, will be in the fray.
At stake: profits from selling copies of the operating systems, as well as profits on computer hardware, applications software, programming tools and other technology to turn the networks into useful business tools.
"There's significant revenue in the high-end PC server market," said David Thacher, manager of the Windows NT product for Microsoft. "A tremendous amount of computing is being downsized as PC platforms become increasingly powerful."
Servers function as a repository for shared data and the hub of communications among the computers on individual workers' desks.
In the past few years, personal computers have begun to act as servers for small networks in, for example, individual company -- departments. But traditionally, large mainframes and minicomputers have been the hub of a corporation's computing system.
That is rapidly changing.
Personal computers are vastly more powerful than they were just four years ago, and the performance of some high-powered work stations rivals that of minicomputers. Within the next few years, advances in microprocessors and other hardware technology are expected to yield desk-top-style computers that can manage corporate computing tasks once reserved for mainframes.
The crucial difference is that personal computers and work stations are far less expensive than the mainframes they will displace.
Such computer "downsizing" threatens the dominance of manufacturers such as International Business Machines Corp., which has long relied on its high-margin mainframe computers for the bulk of its business. But it offers an unprecedented chance for other companies to gain access to once-closed corporate computer rooms.
"The goal is getting influence in the [corporation]. That's why Apple and IBM and Next and Microsoft are all duking it out in that market," said Nancy McSharry, an analyst with International Data Corp. in Mountain View, Calif.
It appears unlikely that any one operating system, of the five or so major contenders, will sweep aside the competition soon.
"I don't think that, in upper-end systems, any operating system becomes the prevalent one in the next three to four years," said analyst and newsletter publisher Andrew Seybold.
Indeed, hardware makers such as Hewlett-Packard Co. say they are prepared -- somewhat reluctantly -- to support a number of operating systems.
"As a vendor, the fewer operating systems you have the better," said H-P spokeswoman Jill Kramer. "It's very costly for us to support more operating systems. But we don't want to get left out."
Of the contenders, the oldest is Unix, developed by AT&T more than 20 years ago. Unix is widely used in scientific and engineering work stations, where its power and flexibility are welcomed. It has found relatively little acceptance with business users, however, because it is difficult to use. Companies such as Sun Microsystems Inc. and NeXT Inc. have spent considerable time and money developing versions of the system with graphic user interfaces and other features to make it more palatable in corporate environments.
During most of the 1980s, Microsoft was a major proponent of Unix. But it has shifted its resources to develop NT, an advanced operating system that can support Windows. Windows itself is really a graphic user interface running on top of DOS, the 11-year-old operating system Microsoft supplied with the first IBM Personal Computer. NT would replace the DOS underpinnings of Windows, running Windows programs on far more sophisticated hardware than DOS can support.
Microsoft also was a partner with IBM in the initial development of OS/2 but began developing NT as its relations with IBM soured.
IBM took over all development of OS/2 and will deliver its first real server version tomorrow. Analysts say that, while IBM is behind Microsoft in marketing the system against Windows, the company has come up with a technically sound product.