COBOL-68 Language Manual Aug81

This document is the TOPS-10/TOPS-20 COBOL-68 Language Manual (AA-5057B-TK), revised in August 1981, covering COBOL-68 compiler Version 12B, LIBOL Version 12B, and SORT Version 4C.

The manual serves as a comprehensive reference and user guide for COBOL-68 programmers on DEC's TOPS-10 (V7.01) and TOPS-20 (V4) operating systems. It is not a beginner's tutorial but assumes prior knowledge of the COBOL-68 language.

Key areas covered include:

• COBOL-68 Language Definition: Detailed explanations of COBOL-68 symbols, terms, program structure (Identification, Environment, Data, and Procedure Divisions), source program formats, and the COBOL library facility.
• Divisional Specifications: In-depth descriptions of each COBOL division, including configuration settings, input/output controls (e.g., SELECT, RESERVE, FILE STATUS), data descriptions (e.g., PICTURE, USAGE, OCCURS), and all COBOL verbs (e.g., ADD, MOVE, OPEN, READ, WRITE, PERFORM, SORT).
• Utility Programs: Comprehensive guides for using ISAM (Indexed-Sequential File Maintenance), LIBARY (Source Library Maintenance), COBDDT (Debugging), and RERUN (Program Restart).
• File Handling & Organization: Covers various recording modes and file formats (ASCII, SIXBIT, EBCDIC, Binary), file organization (sequential, random, indexed-sequential), and mechanisms for simultaneous file updates.
• Program Modularity & Performance: Explores program segments, subprograms, overlays, inter-program communication (including FORTRAN and MACRO subprograms), and techniques for optimizing COBOL-68 program performance.
• Appendices: Provides essential reference data such as COBOL reserved words, collating sequences, logical name definitions, and tape handling instructions.