Dec/X8 Module "Notfun" Non-Functional Iot Test

Summary

The "NOTFUN" software module is a diagnostic tool designed for DEC/X8 systems (PDP-8/I, 8/L, 8/E, 8/M, and PDP-12). Its primary purpose is to verify that "non-functional" IOT (Input/Output Transfer) instructions—those not intended for system use—do not adversely affect the system state or execution flow when triggered.

Key functions include:

• Verification: It executes a user-provided list of IOTs and ensures the Accumulator (AC) remains unaffected and that no improper "skips" occur.
• Initialization: Users input a list of existing device codes used in their specific system configuration; the program then validates these codes.
• Error Handling: Any detected anomaly is reported as a fatal "STAT ERR," at which point the diagnostic job is automatically terminated.
• Compatibility: The module runs as a background task, requiring low priority and at least two job slots.