The QNX Neutrino Persistent Publish/Subscribe (PPS) service is a small, extensible publish/subscribe service that offers persistence across reboots. It's designed to provide a simple and easy-to-use solution for both publish/subscribe and persistence in embedded systems, answering a need for building loosely connected systems using asynchronous publications and notifications.

With PPS, publishing is asynchronous: the subscriber need not be waiting for the publisher. In fact, the publisher and subscriber rarely know each other; their only connection is an object which has a meaning and purpose for both publisher and subscriber.

The PPS design is in many ways similar to many process control systems where the objects are control values updated by hardware or software. Subscribers can be alarm handling code, displays, and so on. Since there is a single instance of an object, persistence is a natural property that can be applied to it.