Open Document Architecture
|Developed by||ITU-T, ISO|
|Type of format||Document file format|
|Standard(s)||CCITT T.411-T.424, ISO 8613|
The Open Document Architecture (ODA) and interchange format (informally referred to as just ODA) is a free and open international standard document file format maintained by the ITU-T to replace all proprietary document file formats. ODA is detailed in the standards documents CCITT T.411-T.424, which is equivalent to ISO 8613.
ODA defines a compound document format that can contain raw text, raster images and vector graphics. In the original release the difference between this standard and others like it is that the graphics structures were exclusively defined as CCITT raster image and Computer Graphics Metafile (CGM - ISO 8632). This was to limit the problem of having word processor and desktop publisher software be required to interpret all known graphics formats.
The documents have both logical and layout structures. Logically the text can be partitioned into chapters, footnotes and other subelements akin to HTML, and the layout fill a function similar to Cascading Style Sheets in the web world. The binary transport format for an ODA-conformant file is called Open Document Interchange Format (ODIF) and is based on the Standard Generalized Markup Language and Abstract Syntax Notation One (ASN.1).
One of the features of this standard could be stored or interchanged in one of three formats: Formatted, Formatted Processable, or Processable. The latter two are editable formats. The first is an uneditable format that is logically similar to Adobe Systems PDF that is in common use today.
The intent was to have a universal storable and interchangeable document structure that would not go out of date and could be used by any word processor or desktop publisher. This was to solve the problem of the software applications that had their native file formats continually updated, sometimes rendering older native formats obsolete and therefor unusable. There was a large financial impact on companies that used ad hoc standard applications, such as Microsoft Word or WordPerfect, because of the need to maintain groups of people whose sole job was to import old stored documents into the latest version of the application before it became unreadable. The intended result of this standard was that companies need not commit to an ad hoc standard for word processor or desktop publisher applications, because any could be used to read and edit long stored documents.
The initial round of documents that made up ISO 8613 was completed after a multi-year effort at an ISO/IEC JTC1/SC18/WG3 meeting in Paris La Defense, France, around Armistice (Nov. 11) 1987, called "Office Document Architecture" at the time. CCITT picked them up as the T.400 series of recommendations, using the term "Open Document Architecture". Work continued on additional parts for a while, for instance at a ISO working group meeting in Ottawa in February 1989. Improvements and additions were continually being made. The revised standard was finally published in 1999. However, no significant developer of document software chose to support the format, probably because the conversion from the existing dominating word processor formats such as Wordperfect and Microsoft Word was difficult and offered little fidelity. It also took an extraordinarily long time to release the format (the pilot was financed in 1985, but the final specification not published until 1999). Given a lack of products that supported the format, in part because of the excessive time used to create the specification, few users were interested in using it. Eventually interest in the format faded.
It would be improper to call the ODA anything but a failure, but its spirit clearly influenced latter-day document formats that were successful in gaining support from many document software developers and users. These include the mentioned HTML and CSS as well as XML and XSL leading up to OpenDocument and Office Open XML.
The standard itself was made available for free download on September 7, 2007 (the "missing" documents T.420 and T.423 do not exist):
- T.411 Introduction and general principles
- T.412 Document structures
- T.413 Abstract interface for the manipulation of ODA documents
- T.414 Document profile
- T.415 Open document interchange format (ODIF)
- T.416 Character content architectures
- T.417 Raster graphics content architectures
- T.418 Geometric graphics content architecture
- T.419 Audio content architectures
- T.421 Tabular structures and tabular layout
- T.422 Identification of document fragments
- T.424 Temporal relationships and non-linear structures