Guide to Realtime Programming

This document, revised in February 1994, serves as a technical manual for developers building realtime applications on the DEC OSF/1 operating system (version 2.0 or higher). It focuses on using the POSIX 1003.4 Draft 11 (P1003.4/D11) interface to achieve timing, predictability, and performance.

The guide covers: - Realtime Programming Concepts: Definitions of hard vs. soft realtime, preemptive vs. nonpreemptive kernels, and process preemption latency. - Process Scheduling: Details on priority levels, fixed-priority scheduling policies (SCHEDFIFO and SCHEDRR), and the nice interface. - Interprocess Communication: Explanations of shared memory, semaphores, message queues, and pipes. - Memory Management: Procedures for memory locking to eliminate paging in time-critical applications. - Signals and Timing: Usage of POSIX signals, high-resolution clocks, and timers. - System Configuration: Instructions for installing the realtime kernel and compiling applications using required libraries.

It includes extensive examples for common programming tasks and technical appendices detailing differences between POSIX drafts and providing a summary of realtime-specific functions.