As of the 1.2 release, regions of this guide are designated with a support level. This support level system, which closely parallels the current Application Environment Specification - User Environment Volume support level system, specifies the commitment OSF makes to the guidelines in that region. The higher the support level, the longer the warning period required before OSF can delete the guidelines, or make an incompatible change in the guidelines. (An incompatible change is one that might require compliant applications to be rewritten.) Support levels, therefore, serve as advisories for application developers because they indicate the length of time that a guideline is guaranteed to remain stable.
During the OSF/Motif Style Guide development process, OSF staff members propose support levels for guidelines, based on criteria defined later in this Preface. OSF members review and comment on these support levels and the rest of the document.
In general, membership review proceeds as follows:
OSF considers all review comments during the development of the OSF/Motif Style Guide and brings important or controversial issues up for further discussion. However, the review process is not a voting process, and OSF does not wait for consensus among the membership before adding new interfaces to the OSF/Motif Style Guide or making other technical decisions.
This section defines the support levels assigned to the guidelines. As previously mentioned, support levels define OSF's commitment to interface definitions by indicating the warning period required to make an incompatible modification or deletion of the guideline. New OSF/Motif Style Guide revisions may introduce upwardly compatible changes at any time, regardless of the support level.
The support levels are as follows:
The following sections explain each support level, and how guidelines move from proposed status (in drafts) to final status (in published versions).
A full-use guideline has the highest support level, so it is the most protected from incompatible modification or deletion.
OSF assigns a support level of full use to guidelines for the following reasons:
There should rarely be a need to remove a full-use guideline, or make incompatible modifications to it. However, if this ever becomes necessary, a full-use guideline keeps its full-use status, but we will publish a warning describing the proposed future change in at least two successive revisions of the OSF/Motif Style Guide before we make the change. This provides time for applications to be altered to deal with a different guideline, and for implementations to prepare for the change.
For example, suppose it becomes necessary to modify a full-use guideline that appeared in Release 1.2 of the OSF/Motif Style Guide. The draft for Release 1.3 shows the guideline as "proposed-for-modification/removal." Assuming the review concludes that this change is appropriate, the guideline in Release 1.3 still has full-use status, but is accompanied by a warning. The warning states that the guideline is scheduled for modification after Release 1.4, and describes the modified behavior. Application developers can now allow for either the original or the modified guideline. Release 1.4 contains the same warning. Release 1.5 provides the modified definition only.
A trial-use guideline is easier to modify or delete than a full-use guideline. There are several reasons why OSF classifies guidelines as trial use instead of full use. A guideline may be under consideration for inclusion in a de jure standard and so may possibly change as a result of the standards process. Or, OSF may perceive that the guideline is new compared to other included guidelines and, therefore, the implementation and use of the guideline may suggest revisions in its definition.
If it becomes necessary to modify or delete a trial-use guideline, it keeps its trial-use status, with warnings about its removal or incompatible change, for one full revision of the OSF/Motif Style Guide. In the preceding example, if the guideline to be modified were a trial-use guideline, Release 1.3 would include the unmodified definition with a warning and description of the change, and Release 1.4 would include the modified definition only.
Draft versions of the OSF/Motif Style Guide give newly added or changed guidelines a ``proposed-for-level'' status, where level is full- or trial-use. In final versions, these guidelines move from ``proposed-for-level'' status to level status. Most existing guidelines retain their support level from the previous revision. A few may carry a proposed-for-change status (described as follows). New guidelines carry a proposed-for-level status.
The following list defines more exactly the AES proposed-for-inclusion and proposed for-change levels.
If this proposal is accepted during the review process, a full-use guideline remains as is, with a warning, for two revisions; a trial-use or temporary-use guideline remains as is with a warning, for one revision. If the proposal is rejected, the guideline remains as is.
To avoid confusion when reading this guide, the entire guide has a global usage level. Each guideline in this guide has this global usage level unless specifically set out differently. To initiate this usage level process, in this version of the OSF/Motif Style Guide all the guidelines have a usage level of trial-use.