FORTRAN II Basic System PDP-9

This document is a programming manual for the PDP-9 FORTRAN II system, designed to assist scientists and engineers in writing programs for the PDP-9 computer. It serves as a reference guide, assuming the reader has a basic understanding of FORTRAN II programming principles.

The manual covers:

• FORTRAN II Language: Introduction to its symbols, words (numbers, variables, commands), and statements (Arithmetic, Program Control, Specification, Input/Output). It details how to prepare a FORTRAN program, including identification fields, statement fields, and required statements like END.
• Arithmetic and Data-Specification Statements: Explains arithmetic expressions, their evaluation, use of parentheses, replacement (equal) signs, internal arithmetic statements, and modes of computation (integers and real numbers). It also covers data-specification statements like DIMENSION for arrays and 2WORD for floating-point storage.
• Program Control: Describes statements for altering program flow, repeating sections, suspending operations, or halting the program, including GOTO statements, DO Loops, CONTINUE, Computed GOTO, Assigned GOTO, STOP, and PAUSE.
• Input/Output Statements: Details I/O assignments, data lists, ordering of data within arrays, and I/O specification statements, including data fields and various formats (I, F, E, X, H, A) for numeric and non-numeric data. It also defines physical records for different I/O devices (Keyboard, Teleprinter, Paper Tape Reader/Punch, Line Printer).
• Subprograms (Functions and Subroutines): Explains how to use and define functions and subroutines, including FUNCTION definition, RETURN statements, CALL statements, and the use of common storage and array names. It also delves into machine language coding within a FORTRAN context, covering symbolic conventions, floating-point commands, and subprogram linking.
• Operating Procedures: Outlines the steps for using FORTRAN with a PDP-9 paper tape system, from preparing programs to compilation, assembly, loading, and execution.
• Diagnostics and Error Messages: Provides a comprehensive list of error messages from the FORTRAN Assembler and the Linking Loader, along with error halts in the FORTRAN Object Time System, to aid in debugging.
• Operating Test: Describes a program designed to test the satisfactory operation of both the FORTRAN System and the PDP-9 hardware.
• Appendices: Includes character code equivalences, use of extended memory, and a FORTRAN summary description.