DEC-10-SBAB-D Creating A PDP-10 Time-Sharing Monitor 196803

This document, "Creating a PDP-10 Time-Sharing Monitor" (DEC-10-SBAB-D, March 8, 1968), outlines the four essential steps for building and loading a customized PDP-10 time-sharing Monitor.

The process involves:

1. Assembling Source Files: Source code files are assembled, utilizing a System Parameter Tape ("S" file) that defines global symbols and feature switches (e.g., FTDISK, FTLOGIN). These switches determine the overall nature of the system (e.g., nondisk, disk nonswapping, disk swapping) and which routines are included. Special channel interrupt and null channel routines have a unique macro-based assembly process.
2. Creating the Monitor Library File: All assembled relocatable binary files are combined into a single Monitor Library file (e.g., SYS40N.REL, SYS40D.REL, SYS50.REL) using the File Update Generator (FUDGE2) program. Files must be specified in a particular order to ensure proper formatting for the subsequent Build process.
3. Building a Customized Monitor: The System Builder (BUILD) program runs interactively, guiding the user through a dialogue to configure the Monitor for their specific hardware. This includes setting device counts, specifying non-standard devices, and modifying global system parameters (e.g., power frequency, memory cycle time, magnetic tape density, priority interrupt channel assignments). Users can also incorporate their own custom Monitor routines.
4. Exec Mode Loading: The final step is to load the saved core image of the customized Monitor into an "empty" machine. This procedure involves setting console switches, loading the TENDMP program (typically from paper tape), and then issuing a command to load the Monitor from a specified DECtape.

Normally, users who only wish to create a system matching their hardware configuration need only perform steps 3 and 4. However, any user intending to rewrite or add code to the Monitor must be familiar with all four steps. The document also mentions debugging the Monitor using the Executive Dynamic Debugging Technique (Exec DDT) program.