DEMO12 Monitor System Technical Reference Manual

This document provides a comprehensive technical reference for the PDP-12 DEMO12 Monitor System. It outlines the system's architecture, operational procedures, and programming guidelines for user applications.

The DEMO12 Monitor runs on a basic PDP-12A configuration, leveraging its VR12 display, LINCtape controller, console Teletype, and up to 6K of memory for user programs. The system is self-contained and manages its operational states and transitions through various control character inputs. Key components include the LOADER, INITLIZE (initialization), SEGØ (interrupt and trap handling), SEG1 (state routines and display functions), and BALLON.

The manual details core memory layouts, tape block allocations, file structures (including the DEMO Index), and input/output processes. It also explains numerous system flags and indicators vital for debugging and modification. Specific sections cover the Monitor's state system, including transition tables, and a list of error and informational messages.

A significant portion of the document addresses programming conventions and restrictions for DEMO User Programs (DUPs). This includes guidelines on interrupt handling, memory usage, LINCtape access (with designated scratch areas and write protection), and the use of specialized OPR instructions. Procedures for preparing DUP TEXT files, which contain summary and help frames, and for creating or modifying the DEMO Monitor tape are also detailed.

Finally, the manual describes operating procedures for loading the system (both one-tape and two-tape configurations), restarting, terminating, and troubleshooting common error conditions.