Device Description Repository
From Wikipedia, the free encyclopedia
Contents |
[edit] Introduction
The Device Description Repository is a concept proposed by the Mobile Web Initiative Device Description Working Group (DDWG) of the World Wide Web Consortium. The proposed repository would contain information about Web-enabled devices (particularly mobile devices). Authors of Web content would be able to make use of the repository to adapt their content to best suit the requesting device. As such it would facilitate the interaction and viewing of Web pages across devices with widely varying capabilities.
Information in the repository would include the screen dimensions, input mechanisms, supported colors, known limitations, special capabilities etc.
[edit] Status
The "requirements for a single logical device descriptions repository"[1] were first published as a W3C Working Draft in April 2006, and completed as a "Working Group Note"[2] in December 2007.
The "DDR Simple API"[3] specification was published as a Working Draft of a proposed W3C Recommendation in April 2008.
[edit] Background
The idea of implementing a Device Description Repository was discussed at an international workshop[4] held by the DDWG in Madrid, Spain in July, 2006. This resulted in a proposal to re-charter[5] DDWG to work on the formal design of the programming interfaces, and ways to populate the repository with data and make this available to anyone who wanted to build Web servers that could adapt content to suit the end user devices.
[edit] Design goals
The architecture of the repository has not been clarified, but a distributed solution is likely. In general, the desirable characteristics of a Device Description Repository are:
- Relevance of data. The DDWG includes content adaptation specialists who have identified a core set of device properties that are useful for adaptation. Other groups are likely to refine this knowledge. Keeping the information up-to-date will also be a challenge.
- Ease of use. The interfaces should map easily to a variety of programming languages, and be as simple to use as other popular adaptation technologies (e.g. WURFL).
- Ease of deployment. Existing technologies like DNS show that global repositories can be deployed on a real-time basis. The W3C is unlikely to specify a particular server architecture. The DDWG has already identified a Web Service interface (e.g. SOAP) as a minimum requirement, and implementations are free to create the logic any way they wish (e.g. relational database queries) so long as the formal interface is supported.
- Assured interoperability. The varied nature of the Web requires that the repository interfaces and data formats can be supported by the largest number of Web technologies. Formal descriptions of APIs and Data Vocabularies will be necessary.
- Assured availability. If Web servers rely on device descriptions to provide adapted content, then these descriptions must be available at all times. Multiple repository hosts and support for data caching are likely to be part of the repository architecture.
- Efficiency. To ensure that the repository does not create unnecessary burden on scarce resources, the load should be distributed and data formats should be designed for simple processing.
- Industry support. The backing of organisations like W3C and the Open Mobile Alliance, and of vendors, service providers and device manufacturers will be critical.
The interface to the repository should provide the means of retrieving contextual information based on some evidence that identifies the context. Typically this means providing request headers through the interface and subsequently retrieving values for named properties. The W3C DDWG is providing an initial vocabulary of such properties (based on a formal ontology), and an interface for the retrieval functionality. The interface will be designed in a language-neutral manner to enable many implementations on many platforms.
[edit] Notes
- ^ David Sanders (April 10, 2006). Device Description Repository Requirements 1.0 (Draft). W3C (MIT, ERCIM, Keio). Retrieved on 2007-12-10.
- ^ Kevin Smith (December 17, 2007). Device Description Repository Requirements 1.0. W3C (MIT, ERCIM, Keio). Retrieved on 2008-04-09.
- ^ Jo Rabin, José Manuel Cantera Fonseca, Rotan Hanrahan, Ignacio Marín (April 4, 2008). Device Description Repository Simple API. W3C (MIT, ERCIM, Keio). Retrieved on 2008-04-09.
- ^ International Workshop on the Implementation of a Device Description Repository. W3C (MIT, ERCIM, Keio) (July 12, 2006). Retrieved on 2008-04-09.
- ^ MWI Device Description Working Group Charter. W3C (MIT, ERCIM, Keio) (December 5, 2006). Retrieved on 2008-04-09.
