Data in the NSCLDAQ system are distributed online through ring buffers. While a ring buffer, at its lowest level, is just a stream of bytes produced by a producer and consumed by zero or more consumers, in practice, a structure is layered on top of this byte stream.
Items are placed by producers as Ring Items. A Ring Item consists of a header and a payload. The header contains the complete size of the item and an item type. As NSCLDAQ has evolved, so too have the formats of the payloads for various item types. This makes writing programs that can process data from all versions of NSCLDAQ difficult to write correctly.
This document describes a set of libraries which should ease this burden, and allow you to very simply write programs that can operate on data from any of the NSCLDAQ data formats.