LWN.net Weekly Edition for June 6, 2002

Fun with software patents

Much of this week's LWN front page has to do with software patents, and how to respond to them. Doubtless some people are tired of the topic, but it remains important. The shape of our free software systems in the future will, unfortunately, be much affected by software patents. It is important that we figure out how to deal with them.

Comments (3 posted)

Red Hat and software patents

Software companies worry about software patents; an infringement suit can, after all, ruin your whole day. Red Hat has decided that the best way to deal with the problem of software patents is to get into the game. So, the company has applied for (at least) two patents:

• Embedded Protocol Objects, mixture of static and dynamic responses to HTTP requests, as found in TUX.
• Method and apparatus for atomic file lookup, a lookup optimization in the Linux dentry cache.

Both of these techniques show Ingo Molnar as the inventor. And where might one find the patented technology?

(This news was originally reported (in Italian) on FreeGo).

After letting people worry over the holiday weekend, Red Hat issued a statement of position on software patents. According to that statement, Red Hat's intent is defensive:

Red Hat, too, has decided to pursue that strategy; it has joined the software patent arms race by arming itself.

What do these patents mean for free software? According to Red Hat's position, not much; the statement includes a promise to not enforce any patent claims against software using an "approved" open source license. So the free software community can relax; Red Hat is simply trying to protect itself from patent suits and will not be exploiting the dark side of software patents.

Not so fast. The situation, unfortunately, is not quite that simple. There are a couple of problems with Red Hat's position that should be kept in mind.

The first of these problems is that a promise on Red Hat's web site only means so much. It is not an enforceable contract that anybody can count on; Red Hat can change its position at any time. A court may take the published promise into account in a future case, but that promise may not keep such a case from happening in the first place. Red Hat, under its current management, seems unlikely to change its approach to patents - the posted promise is undoubtedly sincere. But corporate management and ownership can change quickly - and, with them, posted patent policies.

More disturbing in the short term, however, is Red Hat's list of "approved" licenses. It includes the GPL, the IBM Public License, the Common Public License, the Q Public License, and "any open source license granted by Red Hat." A whole class of licenses, including the LGPL and, crucially, the BSD license, has been excluded from Red Hat's patent promise.

In other words, the various versions of BSD Unix are not welcome to use Red Hat's patented technology. In fact, they can be sued for infringement if they do use that technology. The license wars, it seems, are still being waged, and Red Hat has just launched a new offensive. This is a move which will encourage division in the free software community, to say the least.

The cynical among us could even see this policy as a strike by Red Hat against a whole class of competing free operating systems. That is almost certainly not the case: Red Hat is just trying to ensure that its patent weapons can actually be used. As the company told us:

It's not worth it. Red Hat ships a great deal of software under licenses which, it seems, are now too free: consider the X window system or OpenSSH, for starters. There has been a great deal of exchange of ideas between Linux and *BSD; the FreeBSD VM subsystem, for example, has long been seen as an inspiration by at least some Linux kernel hackers. We have all benefitted from the OpenBSD security auditing work. Red Hat, in the name of patent defense, is cutting off the flow of ideas in one direction. That is not how free software is supposed to work. Red Hat should find a way to deal with software patents that does not alienate a large and valuable part of the free software community.

As a starting point, why not contribute these new patents (and the various gcc patents said to have been originally obtained by Cygnus) to a free software "patent pool"? The patents would be licensed for any use as long as the licensee does not sue any company alleging patent infringement by any free software used or distributed by that company. If it is absolutely necessary to dirty one's hands with software patents, this approach seems more constructive and beneficial to the community.

Comments (23 posted)

ADEOS - avoiding real-time Linux patents

The current systems for performing hard real-time tasks with Linux (RTLinux and RTAI) take the same approach: use a real-time kernel at the lowest level of the system, and run the general purpose kernel (i.e. Linux) as the lowest-priority task. This technique has been patented by Victor Yodaiken, and the patent has been licensed to the community under terms similar to those used by Red Hat: as long as your work is licensed under the GPL, you can use the patented technology without paying royalties.

This patent and its license have been the subject of endless controversy in the free software community. In particular, developers and users of RTAI have always felt a little nervous, especially when the RTAI core was licensed under the LGPL. The recent relicensing of the RTAI core was undertaken to be sure of compliance with the patent license, but not everybody has been satisfied. In particular, people who wish to run or distribute proprietary systems using RTAI have been unsure of their status.

An obvious solution, one might think, would be to not use the patented technology; until recently, however, alternatives have been somewhat scarce. That situation may have changed, however, as the result of the announcement of the upcoming first release of ADEOS.

ADEOS is, essentially, a small "nanokernel" which takes charge of low-level hardware resources (interrupts in particular). Any number of higher level operating systems can run in parallel on top of ADEOS; they run independently and know little of each other. ADEOS implements an abstraction called an "interrupt pipeline," which is essentially an ordered list of systems which are interested in a particular interrupt. Real-time systems put themselves at the head of the list, and are thus able to respond quickly to interrupts. General purpose systems can handle any interrupts which the real-time systems allow to pass down the pipeline.

The idea of running multiple operating systems over a small, low-level kernel is not particularly new; IBM has been doing it for decades. It is interesting, however, in that the ADEOS developers claim that it is suffiently different from the RTLinux approach that it is not covered by the patent. The reality of the situation, however, may not be determined until a fair number of lawyers have been involved.

The RTAI project plans to move over to ADEOS and thus, with luck, free itself of patent worries. Whether RTAI will be able to rid itself of the persistent claims that it is a derivative of RTLinux could be another story. RTLinux supporters will point out strong similarities between a number of source files in the two projects. If RTAI really used RTLinux code at the beginning, and released that code under a different license (even if that license was the LGPL), the project has, in theory, lost its rights to use that code. Nobody has seriously pursued a GPL infringement claim against RTAI, but, as long as the allegations persist, such an action is a possibility.

Meanwhile, ADEOS embodies a different approach to dealing with software patents: find a way to work around them. From the press release:

This approach has been taken with other patents: using JPEG and PNG files to get around the GIF patent, and Ogg Vorbis as an alternative to MP3, for example. As software patents proliferate in the U.S., however (and possibly spread to Europe), it will get always harder to dodge them all. And tiresome as well. Software patents remain a threat to free software.

(See also: a more detailed, technical description of how ADEOS works.)

Comments (none posted)

UnitedLinux makes its launch

After a suitable period of pre-launch hinting, the UnitedLinux initiative sent out a press release announcing its existence. A press release is about all there is, at the moment; the realization of the goals behind United Linux will take a little longer.

UnitedLinux is a joint venture between Caldera, Conectiva, SuSE and Turbolinux. Essentially, the four will be combining much of their Linux distribution development operation. The advantages of this combination are fairly clear: much duplicated work can be eliminated, and the companies will have at their disposal a single base distribution which is standards compliant and uniform. The companies' four distributions have all lacked sufficient market share to inspire software vendors to target them. One, larger distribution, it is hoped, will be more successful at attracting the independent software vendors of the world.

An alpha release of UnitedLinux, apparently based most heavily on SuSE's distribution, is due in the near future, with the general release happening in the fourth quarter of this year. Each distributor will then add its own special offerings and sell the result under its own brand. Interestingly, the UnitedLinux release plans page mentions KDE 3.0, but says nothing about GNOME. Several "installation languages" will be supported.

The biggest controversy over UnitedLinux would appear to be whether it will be available as a free download. The initial statements from the group have been mixed. We will have to wait and see on that one. A more worthwhile question might be: will UnitedLinux expose its development version the way Mandrake, Debian, and Red Hat (sort of) do? Inviting outsiders into the development process is a far more convincing sign of openness than distributing free binaries.

The other open question, of course, is: what other companies might join? An invitation has been extended to Red Hat, but nobody really expects that company to want to be a part of UnitedLinux. MandrakeSoft is a more interesting possibility; it is by far the largest other distributor which is not currently a part of the group. Thus far, MandrakeSoft has been awfully quiet about UnitedLinux.

If UnitedLinux lives up to its promise, it could become the platform upon which a new generation of distributions can grow. Doing UnitedLinux right, however, will require keeping both the free software community and the commercial world happy. This goal should be achievable; we wish this group luck.

Comments (1 posted)

The new LWN.net site

Back in August, 1998, LWN made a major site change: we went from the "everything on one big page" format to the multi-page format that is still used for the weekly edition. We got over 100 complaints about that change - people liked things the old way. So we restored the "one big page" as an option, and it is still used by a (declining) number of LWN readers.

As you can see, LWN has changed format again; see our introductory posting for a description of what has changed. We'll say here, however, that what has not changed is LWN's content. The presentation is different, and a number of new capabilities have been added, but our writing remains as always.

By the standards of 1998, the reaction to this change has been relatively muted. Some people like the new site, others do not, but there has been no avalanche of complaints. Which is fine with us. We are certainly interested in hearing from our readers (at lwn@lwn.net) about ways we could improve the new site; we do request, however, that commenters be specific about what they do or do not like. We try to respond to specific complaints, but there's not much that we can do with a message that just says "I hate the new site."

There are certainly some rough edges on the new site. Bear with us, and we'll do our best to straighten them out. Meanwhile, please check out the new features, and, we hope, enjoy the new LWN experience.

(Note that people who want to see something that resembles the old site can bookmark lwn.net/current, which always gives the current weekly edition, or lwn.net/current/bigpage, which is the "one big page" format).

Comments (20 posted)