Recent developments in the ASDEX Upgrade data acquisition environment

ASDEX Upgrade today delivers approximately 25 GBytes of data per week. To m anage this demand, which in fact is a growth by a factor of two in the last 2 years, several improvements to the data acquisition (DAQ) system have be en made to avoid bottlenecks and to enhance the usability, Modifications we re done to the diagnostic clients to speed up the storage of big diagnostic files to the central analysis server. The diagnostic synchronization serve r has been modified to handle wait requests not only for raw but for any le vel of evaluated data files. The central analysis server has been upgraded to deliver the power to do synoptic data analysis on up to 500 MBytes/shot on a single multiprocessor machine in shared memory. Additionally a cluster of ten workstations for parallel applications has been built up for MHD eq uilibrium calculations and other CPU-intensive tasks. The Andrew File Syste m (AFS) archive servers have been upgraded to more disk capacity, a redunda nt storage architecture and faster network connections. However, as a basis for these improvements the network backbone and the server connections hav e been moved from FDDI to Gigabit-Ethernet and single workstation connectio ns from Ethernet to Fast-Ethernet. Performance analysis results give an imp ression of the achieved improvements. Other projects in conjunction with th e DAQ system at ASDEX Upgrade are the 'hotlink' interface system developmen t for the Soft-X-Ray and Mirnov-Probes diagnostics and the 'S-link' develop ment for an enhanced electron cyclotron emission (ECE) diagnostic. Both wil l serve as prototypes for future real-time diagnostics, which shall be able to deliver processed data in real-time to other systems - especially exper iment control - to achieve a possibly better experiment performance. (C) 20 00 Elsevier Science S.A. All rights reserved.