Thoughts on an Upcoming Patent War
Until now, Microsoft has had every incentive not to press for patent claims against competing products. First, they have been convicted of antitrust activity, and such action may lead to court-mandated licensing to competitors. But more importantly, such news could be taken by the industry as acknowledgement of the legitimacy of competition. By this thinking, suing over patent infringement in Linux would be good for Linux and bad for Microsoft. Such suits could therefore actually lead to marketshare losses for Microsoft.
It is true that things are changing. Such a suit today would not necessarily boost Linux's stature in the server market where it is already established, but it would require suing Microsoft customers for migrating away from Microsoft products. Additionally the court-mandated licensing concerns would still apply. So, it is still a lose-lose proposition for Microsoft as they would possibly be losing control over intellectual property and would certainly lose goodwill. So such a suit today would continue to boost Linux's market share at the expense of Windows.
The current Microsoft strategy appears to be that of providing moral and sometimes financial support to parties which litigate over Linux. Currently, the only party to do this, SCO, has had very little success in the courts, and my reading of their complaints has lead me to believe that they are not litigating at all over allegations of intellectual property in the Linux kernel itself, regardless of their press releases. Their lawsuit against Daimler-Crysler has been largely dismissed, their slander of title lawsuit over ownership of the relavent copyrights against Novell has been dismissed once and may be dismissed again. Their other suits notable in that they are not claiming ownership of any code in the Linux kernel in their actual complaints. If, as I expect, SCO loses the IBM counterclaim 10 (non-infringement of IBM's Linux activities), then I would expect Linux to benefit both from the focus that the suits have given and the vigorous defence of Linux by IBM, Novell, Red Hat, etc.
So copyright litigation does not seem to be a threat to Linux, at least not at the moment. What about patent litigation?
Patents and Licensing regarding Antitrust Law
Again, I am not a lawyer. If you really need analysis of this issue, hire an attourney.
In the past, the courts have generally held that patents cannot be used by a monopoly to prevent vital competition or to further activity prevented in antitrust activities. Thus one possible result of a suit by Microsoft is that it may be possible to force Microsoft to license such patents in terms compatible with the GNU General Public License (royalty-free, perpetual for all users of software under this license). This would be a more likely scenario in an interoperability project like Samba than in the Linux kernel.
For the Linux kernel, it may be possible to simply rewrite portions of the code to avoid the patents, and prevent Microsoft from being able to seek damages from users under antitrust laws. Also, prior art may be usable to weaken, narrow, or even overturn certain patents held by Microsoft.
Other Roads to Interoperability
Even if certain products, such as Samba, become problematic for patent reasons, there are other ways to enforce interoperability. In my opinion, such encumberances would be more likely in the event that Microsoft has already lost substantial marketshare on the desktop (or perhaps in countries which recognize software patents but are unwilling to force licensing in response to antitrust violations).
Interoperability can be achieved in any of three ways. The first is to provide network services on open source platforms which interoperate with windows-native services. This is the most dangerous approach, patent-wise, but it is often necessary because it allows one to add open source software to their network without any costly migrations. Samba embodies this approach.
The second approach can be the development of clients on Windows which utilize open standards (such as NFS). Microsoft Services for UNIX takes this approach. This is most useful when integrating Windows systens into existing UNIX or Linux networks.
A varient of these two strategies is the development of gateways which can allow clients using one method to use resources using a different one. For example, SFU provides a NFS gateway service and it is possible to do something similar using Samba.
The third strategy is fundamentally different. It is quite possible to develop methods for accessing network resources, such as files and printers, which are designed to be cross-platform from the beginning. OpenAFS, for example, provides distributed, fault-tolerant, secure file access across different platforms.
Assuming we don't see patent encumbrances killing open source interoperability products before Linux gains substantial marketshare on the desktop, such litigation in an attempt to force people to use Microsoft software may instead force people to consider larger migrations away from Microsoft software. Even if such a campaign were to be begun now, I think that it would still force companies to more seriously consider using open source software in larger roles.
How we should react as a community:
There are several things we can do to, in my opinion, to help protect ourselves from this upcoming patent war. Most of these are already underway.
The first is to attempt to actively challenge Microsoft patents which are important to open source software. Current work on this direction does include Pubpat's petition to get the USPTO to re-examine the patent on certain aspects of Microsoft's FAT filesystem. We continue to review such patents and challenge them where appropriate.
Secondly, we need to develop an infrastructure for a communal response to litigation in general. Groklaw has already served to demonstrate that such an infrastructure is not only possible but effective. Such a community resource can be used to facilitate distributed searches for prior art, a forum for legal discussion (where lawyers and non-lawyers can converse), and many other such things. Although Groklaw is extremely valuable, it is run by one person (Pamela Jones). Ideally, we need a foundation-based service which will allow such an infrastructure to be owned by the community in general. Private sites, such as Groklaw would become the extremities of the distributed system rather than the core, as it is today in the SCO battles.
In the end, I do not think that Microsoft or anyone else can win a patent war against Linux (think of the result of Unisys's statements regarding patents and GIF format). In the end, we will end up with something more powerful and better engineered, and with better marketshare.