Software developments for the Readout Unit Prototypes for CMS DAQ System
Orsini, Pollet, Racz, Samyn, Schleifer, Sphicas, P, Sinanis, not provided Currie B.J. · 2000
In the CMS data acquisition system, the readout unit is a fast buffering device for short-term storage of event fragments. It interfaces front-end devices and builder data network. The current Readout Unit prototypes are based on two homegrown hardware boards, the Readout Unit Memory (RUM) and the Readout Unit I/O (RUIO). These boards are equipped with an input/output processor (IOP). Several OS environments for this processor are developed. The software running on those boards will have to setup and control the input and output processes. Fast IOP to host communications are experimented. A software test environment is specifically designed for test and validation of the complex memory management of the RUM. I. THE HARDWARE ENVIRONMENT A. Readout in the CMS data acquisition model In the CMS data acquisition model, the Readout Unit (RU) temporarily stores data from a detector subpart, before forwarding it through the Builder Network to the Builder Unit. Each Builder Unit assembles event fragments for the Filter Units, which are in charge of processing events for Level 2 triggers and of forwarding events that passed Level 2 triggers to the computing services (see Figure 1). Detector Frontend Computing Services Readout Systems Filter Systems Event Manager Builder Networks Level 1 Trigger