Errcon Monitor Detected Error Handling Routines

This document outlines the ERRCON monitor detected error handling routines, designed to manage various system errors detected during operation. Authored by T. Hastings/TH/RCC and dated June 4, 1969, these routines primarily aim to print an error message, stop the affected job, and return control to the monitor's command mode.

Key error types handled include:

• APR (Address Protection Register) Detected Errors: Such as pushdown overflow, illegal memory access, and non-existent memory.
• Address Check Errors: Verifying memory addresses for validity.
• Illegal Instruction and Opcodes: Including specific handling for HALT instructions.
• Illegal UUO (User Unprivileged Operation) Calls: Covering various invalid I/O operations, such as output UUOs for input devices, input UUOs for output devices, illegal device data modes, I/O to unassigned channels, and illegal UUO codes.
• Device-Specific Errors: Including routines for hung I/O devices and bad DECtape directory errors.
• Unexplainable Monitor Errors: Generic catch-all for monitor-level issues.

The routines utilize various sub-routines to print diagnostic information like the Program Counter (PC) value (in octal or decimal), device names, and specific error messages (e.g., "ERROR IN JOB N"). The system aims to save relevant job and system state information upon error, and some routines allow for the user to potentially continue execution after a HALT instruction.