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Volume 6B: Motif Reference Manual, 2nd Edition

The ["Open Motif" license] allows the sources and objects to be used free on operating systems that are themselves open source systems

There are some restrictions.... Open Motif's license is more like the FreeBSD license than GNU.

[Inspection of the sources themselves] has in the past been reserved for the select few who had the money to acquire them.

The announcement is very good news for the Motif community and for the UNIX community as a whole.

Motif Goes Open

by Antony Fountain

At last, Motif sources become freely available. The license covering the release of "Open Motif" allows the sources and objects to be used free on operating systems which are themselves open source systems (e.g., Linux and FreeBSD). The initial distribution is a standard Motif 2.1.30.

There are some restrictions: No title or ownership of the software is transferred. A license is required from the Open Group to distribute on non open source platforms. Modifications may be made to the Motif system, and the rights to any such value-added changes belong to the modifier, who may keep these or filter them back to the master sources. If the modifier wishes to distribute a modified system, it must be in binary form. That is, Open Motif's license is more like the FreeBSD license than GNU: There is no absolute obligation to distribute changes in full source so long as the original license is not violated.

What does this mean for Motif's future? First, technically, one of the biggest problems associated with Motif is that writing Motif-derived components has been something of a black art. There are plenty of Motif-compatible components, but relatively few directly sub-classed from Motif itself, despite the fact that Motif 2.X contained enhancements specifically included to ease the task of the widget author.

This relative paucity is due largely to the fact that writing components by referring only to the documentation leaves much to be desired: The necessary understanding, which can only be gained by a thorough inspection of the sources themselves, has in the past been reserved for the select few who had the money to acquire them. This has, however, not proved a significant drawback to the Motif application programming community due to the very large range of compatible custom components available. Whatever Motif itself has failed to provide (which in terms of basic components is very little) could always be acquired in quality from the likes of the KL group and others.

Second, like all software, Motif has its own practical programming quirks. And documentation, Motif's included, has a habit of describing software as it was intended and not as it was implemented. Notwithstanding the thorough documentation provided by the Open Group, in the absence of reference sources, devising workarounds for given situations can be extremely difficult. Previously, the only remedies were experience and news groups.

Third, Motif has been largely locked out from the success of the Linux operating system, which owes a great deal of its success to the open source community. Gnome and KDE, together with the supporting languages GTK+ and Qt, have flourished precisely because the reference sources can be readily acquired at little or no cost. And the open source movement is not going away.

Although common-desktop-environment (CDE) window management is not included in the release, the announcement is very good news for the Motif community and for the UNIX community as a whole. It is important that UNIX preserves as consistent a programming interface at all levels of programming as possible, whether in kernel, system, or application domains.

Diversity is a strength, but we don't need the fragmentation that results when each platform requires an alternative set of distinct APIs. Linux is not UNIX; we all are. Now we can all share the same native windowing system on terms which satisfy the open community, but which reserves the necessary proprietary rights for commercial organisations. The non-inclusion of CDE management under the terms of the license is irrelevant: Motif applications should work with any ICCCM compliant X desktop.

Before we all dive in and modify the Motif sources to suit our own tastes and preferences, I'd like to issue a warning. Motif is mature, purified, debugged, and robust. It runs in an extremely wide range of domains, from the humble and mundane to the large and international. It ports across every UNIX you might care to mention, and others like VMS.

However, I believe that there are certain things which a programmer should not stick his fingers into unless he has precisely the necessary experience and qualifications to do so. And a windowing toolkit which provides a consistent look and feel across the entire component range in these circumstances is one of them. Read, learn, inwardly digest: These are valid uses of the Motif open source codes.

Don't hack: your new features might kill someone, or destroy critical backwards compatibility, or prevent the system from scaling up, or debar it from running seemlessly across the world's languages. You might ruin the portability, or break the connection between Motif and the vast range of compatible third party components, or prevent the toolkit from working with some specific desktop. This is precisely why the Open Group is ultimately in charge of maintaining the standard.

Just remember that there are things like space shuttles, aircraft engines, or stock exchanges where the entire suite of test or main programs have a Motif front end. Now that Motif is becoming more open, we are all collectively responsible for this.

Open Motif is a good first step for the development community. Let's hope the complicated history and licensing of Motif will soon allow Open Motif to become a fully Open Source Product on all systems.

O'Reilly & Associates recently released Volume 6B: Motif Reference Manual, 2nd Edition, by Antony Fountain.

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