Part IV of this guide contains appendixes that summarize message types, kernel utility interfaces, the STREAMS-based terminal subsystem, and frequently asked questions.
Message Types provides a summary of ordinary and high-priority messages..
Kernel Utility Interface Summary provides a summary of the kernel utility interfaces.
STREAMS-Based Terminal Subsystem describes how a terminal subsystem is set up and how interrupts are handled.
STREAMS FAQ provides a collection of frequently asked questions.