Large and small data acquisition systems at JET

Both large and small data acquisition systems have applications in a major physics experiment such as JET. This paper describes the central acquisition and trigger system (CATS) which provides co-ordinated high speed data acquisition for many diagnostics, and also describes the integration into the JET infrastructure of much smaller systems which use commercial PC based acquisition hardware and software. Such PC systems benefit from lower cost and shorter development time compared to embedded bus-based systems.