The summer of 2000 has been another breakthrough period in the history of free software. Several developments in the past few months, taken together, show that even the explosive success of the Linux kernel for PCs and other workstations is about to be eclipsed by much more far-reaching phenomena.
First, IBM's commitment to support for Linux and other free software bore profound fruit at the beginning of the summer. IBM's Linux Technology Center has completed the work to ``port,'' or adapt the Linux kernel for use on IBM's S/390 series of mainframe computers. This means that Linux itself, and all software that can run on a Linux PC, can also run on some of the most impressive large computers IBM ever constructed. In the United States, IBM has launched an aggressive advertising campaign, involving not just technical publications but also full page advertisements in major daily newspapers, to promote the use of Linux and other free software, along with IBM's proprietary software, for employing S/390 computers as e-commerce servers. Even more significant in some respects were the legal arrangements accompanying this announcement. After negotiations I conducted on behalf of the Free Software Foundation, IBM has assigned to the Foundation its copyrights in all of the very substantial work done to make this kernel port.
From the technical point of view, IBM's S/390 port establishes the Linux kernel as the dominant manufacturer's preferred approach to integrating mainframe hardware into the Internet commerce market. From the legal perspective, IBM's decision to have the Free Software Foundation act as steward for its investments in free software demonstrates that one of the world's most successful technology firms now understands that in the Internet Era ownership of code is less important than the protection of open standards.
While IBM has been further establishing free software at the high end of the hardware market, a similar process has been going on at the other extreme of the scale. Firms that specialize in ``embedded Linux'' are helping free software capture an explosively-expanding position in the smallest computers. An increasing number of information appliances, from palmtop computers to personal MP3 players and new digital video recorders that replace VCRs, incorporate versions of the Linux kernel and other free software as the ``platform'' on which specialized applications are constructed. Within the next year or so a whole range of new wireless devices will be coming to market, allowing web browsing, stock trading, auction tracking, and numerous other functions, all based on a free software operating system running free or proprietary applications. The recent unauthorized distribution of an early version of AOL's new access software for wireless handheld devices was widely reported, for example, proving that AOL-Time Warner too finds itself aboard the Linux bandwagon.
Embedded Linux raises new problems for the legal structure of free software distribution. The GNU General Public License, which sets the legal terms for distribution of many critical free software programs--including the Linux kernel--was designed with general purpose computers primarily in mind. The requirement that source code be made available to users on a medium similar to the medium employed for distribution of program object code, for example, is not quite the same requirement when the object code is running from ROM chips embedded in devices that are not meant to be programmed at all by their end users.
This is not to say that the GPL doesn't apply to such situations, or that its terms cannot be fully observed by embedders, just as they are observed by those who sell or give away software distributions like Red Hat, Corel or Debian GNU/Linux. Sellers of hardware with embedded free software have the same obligations that any other distributor of free software has, and they must abide by the rules. But purchasers of products containing free software have sometimes been denied access to the source code of modifications made to the embedded free software, or have even been denied access to unmodified source, in violation of the GPL, when they have requested it from the appliance's manufacturer. In our role as the steward for much of the world's free software, through our ownership of the copyrights that allow us to enforce the GPL, the Free Software Foundation has been devising measures to address these problems in the embedded market. We hope to announce soon some innovative approaches to the protection of free software licenses in this part of the industry.
The spread of embedded Linux combined with the IBM S/390 port establishes the free software operating system throughout the entire range of computers in present use, from handheld appliances to mainframes. Developers who choose to write software compatible with the Linux kernel and the wealth of other free software, including the GNU tools and applications, can now reach the entire span of users, no matter what computers they employ. The dream of ``write once, run everywhere,'' which has been a goal of the software industry for decades, is now being achieved thanks to free software. And as IBM has shown, the world's most sophisticated corporations are recognizing that the only way to achieve this objective is to abandon a legal structure of ``what's mine is mine,'' for the idea that ``what's ours is everyone's.'' In this way a legal revolution, which uses copyright law to secure freedom rather than ownership, is bringing about a technical revolution that not even the Microsoft monopoly, with all its power in the market, could ever achieve. As this revolution consolidates its gains, and all the industries that comprise the Internet society come to depend on the complete portability of software based on standards and implementations that no one exclusively owns, it will become fully clear just how deeply Free Software Matters.Eben Moglen