Last month's announcement that Microsoft and Novell will cooperate to promote harmonious interconnection between the Windows and Linux operating systems used on servers has produced a spate of commentary, much of it along the lines of "what are they really up to?"

From Microsoft's point of view, an old Yogi Barra-ism applies: Deep down, the motives are shallow. Or, if you prefer Sigmund Freud, sometimes a cigar is only a cigar.

In terms of the number of servers shipped, Windows has about 65% of the market, Linux about 20%, various Unixes about 10%, with the rest spread among several specialized systems. The Unix machines are mostly high-end; measured by dollar value, Windows and Unix have 37% and 30% of the server market, respectively, while Linux has 12%. (Thanks to the helpful analysts at IDC for these numbers.)

So Windows and Linux occupy the same commercial space, and, as Microsoft's Steve Ballmer has said, customers want to be able to use both and they want the systems to interoperate.

But the General Public License that governs Linux says that any code that interacts too intimately with code that is governed by the GPL itself becomes subject to the openness requirements of the GPL. This, along with some other GPL provisions, together with some rather murky concerns about possible patent problems on both sides, makes achieving interoperability complicated legally.

The reasons for this lack of interconnection do not interest the customers, who don't want to get involved in fights over IP ownership that would expose them to liabilities or risk shutting down any major applications, and who are indifferent to the philosophical nuances of the fights between "open" and "proprietary" software. They want their suppliers of software to shut up and deal with it.

Customers also want interoperability because, as Steve Ballmer didn't say, any sensible buyer wants more than one source for an important long-term service, such as computational resources. It wants to avoid lock-in on both upgrades and services.

So how does Microsoft reassure customers about lock-in? It's easy. Microsoft itself eliminates the possibility by helping guarantee that the alternative of Linux will be available. This approach works especially well with a customer that prefers Windows-based apps but is tempted by Linux because of its multiple suppliers of both code and services. Microsoft is betting that, head-to-head, its apps can beat Linux in the market if the fear of lock-in is removed.

Some commenters suggest a devious Redmond plot to destroy Linux, but the idea that Microsoft has any hopes along these lines is absurd. Linux is supported with big money and in-kind help from IBM, HP, Sun, Dell, Google, and a roster of other major players. Customers want it available. These factors will not change, so Linux will thrive.

So Microsoft is, exactly as it says, responding to pressure from its customers. It can see significant business upside from doing so, and it would have no realistic chance of driving the competition off the field in any case, so there is no downside.

But from the open source side -- ah, deep down that one's deep.

People talk about "the open source community" as if such a thing existed. The reality is more complex. Many different tribes and sub-tribes graze this ground.

• The Free Software Foundation (FSF) and its followers believe that all software should be open to unrestricted modification and redistribution. They vehemently oppose software copyrights, patents, and secrecy. In a sort of ju-jitsu move, they think property rights in software should be recognized (via the GPL), but only to ensure that no one can claim profit-making property rights in software. They also oppose computerized Digital Rights Management, which means that oppose property rights in any other forms of creative content as well.

• Integrated computer companies, such as IBM, HP, Dell, and Sun, want to commoditize the operating system so as to capture more of the value of the total system for their hardware, services, and proprietary software applications. Also, Linux is, for all practical purposes, a variety of Unix, so it provides these companies with the equivalent of a standardized Unix, and lets them pool resources to maintain a common version and to promote interaction among the various hardware offerings, it instead of each supporting a proprietary version of Unix.

• Sellers of Linux distributions enjoy getting much of their basic input free from "the community" while they keep the money paid for add-ons and services.

• Many code writers have a personal preference for working in the milieu created by the corporate moneymen, in which the code itself - the programmers' focus - is not propertized and the business dimensions are someone else's problem.

• Technical academicians embrace the concept of a scholarly community sharing information, and legal academicians, usually tenured and well-paid, have theories explaining why other people should work for free.

• Applications service providers, such as Google, get invaluable code at no cost except assigning a few programmers to help "the community" and monetary contributions to some foundations.

• Corporate IT departments -- the customers -- like Linux, preferring it for some purposes, and wanting to avoid any Windows lock-in.

The philosophies and interests of these groups are not entirely congruent. But the more pragmatic parts of the open source movement, the commercial interests of all stripes, pretend that differences are small, and they are self-effacing about not speaking for "the community." That role is left to the programmers, particularly the FSF.

These internal divisions and the effort of maintaining the pretense that they do not exist are creating substantial strains within the open source movement.

Microsoft is a proudly commercial enterprise, subordinating the desires of its coders to the exigencies of the market and the demands of the customers. In contrast, the creation myth of the open source movement is that programmers write for each other, not for the customers. The corporate customers that adopt open source software are being allowed to free ride on the coders' work, and they should be grateful, not uppity and demanding. The justification of the Microsoft-Novell deal that "the customers want it" cuts no ice with open source purists.

Furthermore, Microsoft may not want to destroy the open source movement, but the open source movement, at least as embodied in FSF, certainly wants to destroy Microsoft, as a step toward its ambition of eradicating property rights in software, root and branch, not to mention rights in other forms of content. The world's biggest software company is an obvious impediment to this ambition.

From the FSF point of view, the fact that the customers want interoperability is a bug, not a feature. The FSF does not want interoperability, unless this is interpreted to mean that the open sourcers get to use Microsoft code without granting reciprocity. It wants to force a choice between open and proprietary code, with the former winning, perhaps with the help of a few thumbs on the scale from various governments.

Thus, from the FSF perspective, what happens to Novell, or any other commercial entity, is of zero interest, right along with what the customers want. Hence, after a brief period of confusion, one can see the rolling thunder of the attack on Novell for betraying "the community" in various ways, an attack that will not end until Novell repudiates the deal, even if that means that the company dies, since it is not in a good competitive position.

The corporate supporters of open source have not been heard from much, though. Most of them do care what the customers say, and the sort of adamant holy war being mounted by the FSF is exactly what the customers do not want.

Nor do the corporate tribes share the FSF loathing of patents and other forms of intellectual property. Most of them live and die with intellectual property of various sorts. They may think that software patenting has gone too far - an easy call, since everyone thinks this, including Microsoft - but you don't see IBM tossing all of its patents into the public domain.

Nor do you see tech companies offering to renounce their intellectual property in hardware, most of which is, when closely examined, akin to software patents. The difference between a chip design and a software program can be metaphysical. Nor do you see the biggest service provider of all, Google, fulminating against software patents; Google is built on software patents.

Given these factors, it is not surprising that IBM, the gorilla of the corporate-based tribe, had kind words about the MSFT/NOVL deal.

So the battle is just getting warmed up, but the fight will be conducted under the public radar, between the various sects of the open source movement. A basic question is whether the FSF can drag the other supporters of open source into a holy war that is not in their interest, or that of their customers.

But even if the FSF succeeds in starting a war, then what? Novell cannot really be isolated -- that is the irony of open source code. So to the extent that FSF persuades its corporate allies to ignore the desires of the customers, it will weaken them and strengthen Novell, and Microsoft.

And, somewhere, Steve Ballmer is smiling.