TOPS-10/TOPS-20 COBOL-74

This document serves as a comprehensive language manual for the COBOL-74 programming language, specifically for Digital Equipment Corporation's TOPS-10 and TOPS-20 operating systems. Published in October 1985, it reflects Version 12C of the COBOL-74 compiler (CBL74), the object-time system (C740TS), and Version 4C of SORT.

The manual covers fundamental aspects of the language, including:

• Introduction to COBOL-74: Symbols, terms, language elements, and source program formats.
• Divisions of a COBOL Program: Detailed descriptions of the Identification, Environment, Data, and Procedure Divisions, including their clauses, statements, and rules.
• Compiling, Loading, and Utility Programs: Guidance on compiling and running COBOL-74 programs, and detailed information on utilities like ISAM (Indexed-Sequential File Maintenance), LIBARY (Source Library Maintenance), COBDDT (Debugging tool), and RERUN (Program Restart).
• File Management: Explanations of various file formats and organizations, including sequential, relative, and indexed-sequential files, along with recording modes (ASCII, SIXBIT, EBCDIC, Binary).
• Advanced Features: Simultaneous update capabilities, the Report Writer facility for generating formatted reports, program segmentation, subprograms, and overlays.
• Interoperability and Performance: Instructions for calling non-COBOL subprograms (FORTRAN, MACRO) and techniques for improving COBOL-74 program performance through optimization and efficient coding conventions.

Appendices provide critical reference material on differences between COBOL-68 and COBOL-74, a complete list of COBOL reserved words, collating sequences and conversion tables, alternate numeric tests, and defining logical names under TOPS-20. The document also includes a glossary and an index for easy navigation.