PDP-11 Fortran IV

This document serves as a comprehensive programmer's manual for the PDP-11 FORTRAN IV compiler and the associated Object Time System. It is divided into two primary parts: Part I details the language components, data types, arithmetic and logical expressions, assignment statements, control statements (such as GO TO, IF, and DO), input-output transmission, specification statements, and subprogram definitions. Part II covers the FORTRAN operating environment, including procedures for creating object and load modules, error processing, and specific details on how FORTRAN interacts with the PDP-11 hardware and the Disk Operating System (DOS). Appendices provide summaries of statements, the ASCII character set, library subroutines, word formats for various data types, internal subprograms, and a comprehensive list of error messages.