DCF - Document Composition Facility

Enhanced Definition

DCF (Document Composition Facility) is an IBM mainframe program product used for high-quality, batch-oriented document formatting and text processing. It interprets Generalized Markup Language (GML) and SCRIPT commands to produce print-ready output, primarily for high-volume printing environments on z/OS. Its core function is to transform structured text and formatting instructions into composed documents. DCF (Document Composition Facility) is a powerful IBM mainframe text processing and document formatting system used to produce high-quality, complex documents, reports, and publications. It processes source files containing text and specialized formatting commands written in the SCRIPT language, transforming them into print-ready output, often in AFP format.

Key Characteristics

- Command-Driven: Utilizes a powerful set of SCRIPT commands (e.g., .h1 for heading, .li for list item) embedded within text files to control document layout and appearance.
- GML Processor: Serves as the primary processor for Generalized Markup Language (GML) documents, allowing for semantic markup that separates content from presentation.
- Batch Execution: Typically runs as a batch job under z/OS, processing large documents or multiple documents efficiently without user interaction.
- AFP Output Generation: Frequently generates output in Advanced Function Presentation (AFP) format, enabling device-independent printing with rich text, graphics, and bar codes.
- Customization and Extensibility: Supports user-defined macros, symbol tables, and system variables, allowing for highly customized formatting and dynamic content generation.
- BookMaster Integration: Forms the foundation for BookMaster, an IBM GML application that provides a comprehensive set of tags for creating complex technical manuals and books.

Use Cases

- Technical Documentation Publishing: Creating and maintaining large, complex technical manuals, reference guides, and product documentation for internal and external distribution.
- High-Volume Report Formatting: Generating sophisticated reports, statements, invoices, and other transactional documents with precise layouts for mass printing.
- Automated Forms Generation: Producing standardized forms, letters, and templates that can be populated with data from mainframe applications.
- Legal and Regulatory Document Production: Ensuring consistent formatting and compliance for legal briefs, regulatory filings, and policy documents.

Related Concepts

DCF is intrinsically linked to GML (Generalized Markup Language), acting as its primary interpreter on the mainframe, and often produces output in AFP (Advanced Function Presentation) format, which is IBM's architecture for device-independent document printing. It is frequently invoked via JCL (Job Control Language) as a batch job and is the underlying engine for BookMaster, a higher-level GML application for structured publishing. Its output is often managed and routed to printers by IP PrintWay or other print management systems.

Best Practices:

Leverage GML/BookMaster: Prioritize using GML tags (especially BookMaster tags) over raw SCRIPT commands where possible, as GML promotes structured content and better maintainability.
Modular Document Design: Break down large documents into smaller, logical components (e.g., chapters, sections) stored in separate source files, which improves maintenance and processing efficiency.
Version Control: Implement robust version control for all DCF source files (GML, SCRIPT, macros) to track changes, facilitate collaboration, and enable rollback capabilities.
Optimize for AFP: Design documents with AFP capabilities in mind, utilizing features like overlays, page segments, and font libraries to enhance document quality and reduce print costs.
Thorough Testing: Always test DCF jobs with representative data and target print devices to ensure correct formatting, proper font rendering, and optimal performance before production deployment.