Document Content Architecture
| Industry | Information technology |
|---|---|
| Founded | June 16, 1911 in Endicott, New York, United States |
| Headquarters | Armonk, New York , United States |
| Products | Document Content Architecture (DCA), DisplayWrite, OfficeVision/400, Advanced Function Presentation (AFP) |
Document Content Architecture (DCA) is a standard developed by IBM in the early 1980s, designed primarily for text documents on mainframe and IBM i platforms. It laid the groundwork for the file format used by DisplayWrite and was subsequently expanded into MO:DCA (Mixed Object Document Content Architecture), which supports embedding various data file types.
The purpose of DCA was to harmonize document formats across IBM’s word processing systems, including the IBM PC, mainframe computers, the IBM Displaywriter System, and the IBM 5520 Administrative System.
DCA defines two distinct document categories:
- Revisable-Form Text (DCA/RFT), which allows editing.
- Final-Form Text (DCA/FFT), intended for output on specific devices and not editable.
Description
DCA specifies a data stream format that represents a document and can encompass fonts, overlays, and resource objects necessary for accurate rendering. It also includes resource components such as indexes and tags to facilitate searching and navigation.
The MO:DCA standard serves as a container holding multiple document objects, each governed by its own content architecture:
- Presentation Text Object Content Architecture (PTOCA) – manages formatted text with attributes like font style and color.
- Image Object Content Architecture (IOCA) – handles resolution-independent images.
- Graphics Object Content Architecture (GOCA) – supports vector graphics; AFP GOCA is utilized within Advanced Function Presentation environments.
- Bar Code Object Content Architecture (BCOCA) – accommodates a variety of barcode types.
- Font Object Content Architecture (FOCA) – describes font information.
- Color Management Object Content Architecture (CMOCA) – manages color data.
Each architecture uses binary structured fields to define its respective content object.
Revisable-Form Text
Revisable-Form Text (RFT or RFT-DCA), sometimes referred to as Revisable Format Text, belongs to the DCA family. It was employed by IBM DisplayWriter versions 4 and 5 word processors running on System/360 and 370 mainframe computers, as well as by OfficeVision/400, to enable the transfer of formatted documents between systems.
This format differs from Final-Form Text (FFT or FFT-DCA), which is designed solely for output purposes and does not support editing.
History
The effort to create international standards for DCAs commenced in 1980 at IBM Rochester with a team specializing in MODCA, RTOCA, and PTOCA architectures. Their objective was to build internal consensus at IBM while involving the global community early on, drawing lessons from the lengthy SGML standardization process. IBM’s extensive experience with mainframe document content highlighted the necessity for standardized architectures catering to both revisable and final-form text.
In 1981, development shifted to IBM Austin near Round Rock, Texas, where progress continued amid mixed outcomes. By 1987, the project moved to IBM Dallas Programming Center, maintaining activity until its termination in 1998 due to market shifts favoring PC-centric solutions. Despite completing the DCA architectures after nearly two decades, no significant adoption occurred.
Meanwhile, the personal computer market embraced HTML, which utilizes a simplified subset of SGML for editable text. Microsoft Word adopted a comparable internal data stream format for editable documents. At the same time, Adobe Systems introduced the printable document format PDF, which gained widespread acceptance by 2008 through strong user demand rather than formal standardization efforts. This pragmatic approach outpaced traditional standards development.
The dominance of proprietary formats such as PDF and HTML effectively marginalized the DCA consensus model. Today, word processing applications frequently export documents as PDFs using built-in print functions, reflecting market preference for practical solutions over prolonged standardization processes.
Following the closure of IBM’s Dallas Programming Center in 1998, most of the original architects retired or departed, bringing IBM’s involvement with DCA architectures to an indefinite halt.
See also
- Advanced Function Presentation
- Rich Text Format (RTF) – a markup language occasionally mistaken for Revisable-Form Text.
- List of document markup languages
External links
- Official website of the AFP Consortium
- U.S. Patent No. 5,513,323