System Traps

This document outlines the design and implementation of 'System Traps' within the RSX-11D operating system. It describes how the system allows tasks to respond to specific events or fault conditions—such as stack overflows or I/O completions—by executing designated service routines. The document covers the mechanisms for connecting and disconnecting service routines via the 'SET SYSTEM TRAP VECTOR' directive, the requirements for writing re-entrant code for asynchronous traps, and technical details regarding stack usage, register preservation, and execution flow during trap handling. A list of defined system trap identification numbers is provided, ranging from I/O completion and timer events to hardware faults and power failure recovery.