PDP-9 Advanced Software System Monitors

This document provides a comprehensive guide for preparing and operating programs within the PDP-9 Advanced Software System Monitors. The system is designed for high relocatability and adaptability to various hardware configurations, facilitating program preparation, compilation, assembly, debugging, and execution.

It details three main monitor systems, each offering increasing levels of sophistication and functionality:

1. I/O Monitor: The foundational system, primarily for basic PDP-9 setups using paper tape or card I/O. It manages core input/output operations through the Input/Output Programming System (IOPS).
2. Keyboard Monitor: An expansion of the I/O Monitor for systems equipped with bulk storage devices. It adds capabilities such as Teletype keyboard command processing, dynamic I/O device assignment, and automated program management (storing, calling, loading, and executing programs), along with batch processing features.
3. Background/Foreground Monitor: The most advanced system, extending the Keyboard Monitor for time-shared and real-time environments. It enables the concurrent execution of high-priority, protected FOREGROUND tasks (e.g., real-time data acquisition) and lower-priority, unprotected BACKGROUND tasks (e.g., compilations or debugging runs), thereby optimizing system hardware and processing time.

The software suite includes essential programs like the FORTRAN IV Compiler, MACRO-9 Assembler, Dynamic Debugging Technique (DDT), Text Editor, Peripheral Interchange Program (PIP), Linking Loader, and System Generator. Each monitor system has specific hardware prerequisites, with the more advanced monitors requiring additional memory and I/O options.