Tru64 UNIX

{Tru64 UNIX Guide to Realtime Programming}

This guide is intended for experienced application programmers using HP Tru64 UNIX systems to write or port realtime applications. It primarily describes how to utilize POSIX 1003.1b functions, in conjunction with other system and library functions, to develop applications requiring timely and predictable responses to external events.

The document covers core realtime programming concepts and system capabilities on Tru64 UNIX, including:

• Realtime Overview: Defining realtime applications (hard vs. soft) and their need for predictability and fast I/O throughput.
• System Capabilities: Highlighting features like a preemptive kernel for low process preemption latency, fixed-priority scheduling policies, realtime clocks and timers, memory locking to prevent paging, asynchronous and synchronized I/O, queued realtime signals, and interprocess communication facilities (shared memory, signals, semaphores, messages).
• Process Synchronization: Techniques for coordinating process execution, such as waiting for specified periods, semaphores, communication, or other processes.
• POSIX Standards: Emphasizing conformance to POSIX 1003.1b for portability and enhanced realtime functions.
• Building Realtime Applications: Instructions on defining the POSIX environment and compiling/linking with necessary realtime libraries (librt, libaio).
• System Tuning: Discussion on improving realtime responsiveness by minimizing paging, enabling kernel preemption, managing priorities, and optimizing device drivers.

In essence, the guide serves as a comprehensive resource for developing high-performance, predictable applications on Tru64 UNIX by leveraging its specific realtime extensions and POSIX-compliant functionalities.