common

This document, dated June 4, 1969, is the "MONITOR COMMON DATA AREA AND CONFIGURATION DEFINITION V437" for Digital Equipment Corporation's PDP-6 and PDP-10 time-sharing monitors. It serves as a comprehensive, low-level specification and assembly-time configuration file that defines the fundamental structure, resources, and operational parameters of the monitor.

Key areas detailed in the document include:

• System Resources: Assignments for system accumulators, temporary storage, and general system parameters.
• Device Management: Extensive definitions for various I/O devices (TTYs, mag tapes, dectapes, disk types like RA10, RP10, RD10, Data Products, card readers, line printers, displays, paper tape), including their characteristics, status words, data block structures, dispatch table entries, and program interrupt (PI) channel assignments and handling routines.
• Job Management: Detailed descriptions of job status (JBTSTS), covering memory allocation, scheduling states, execution privileges, error conditions, and the mechanisms for core allocation, swapping, and virtual address space.
• Configuration Parameters: A substantial part of the document outlines variables and prompts used by a MONGEN DIALOG program to customize the monitor for specific hardware setups and operational environments during the assembly process.
• System Initialization & Error Handling: Entry points and data for monitor startup (SYSINI), system crash recovery (CRASHX, SYSTOP), and the handling of unimplemented instructions or unusual I/O events (UUO Traps).
• System Macros: A set of utility macros (NOSCHED, SHUFFLE, ENABLE, DISABLE, etc.) to control core shuffling, scheduling, and PI channel operations programmatically.

In summary, this document acts as the foundational blueprint for building and configuring the DEC time-sharing monitor, enabling it to manage multiple user jobs and diverse I/O hardware specific to the PDP-6 and PDP-10 architectures of that era.