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We show how commodity CPU, networking and memory components greatly simplify a sophisticated trigger system designed for the demanding environment of a high data rate hadron collider experiment operating at 2 x [10.sup.32] [cm.sup.-2][s.sup.-1]. The trigger system is based on an 8-fold way, 3-level architecture capable of processing over 22 million data channels at a crossing rate of 2.5 MHz with a mean value of 6 interactions per crossing. Although originally designed for a B-physics experiment at the Tevatron, the flexible and highly scalable nature of the design should also be relevant to other next generation hadron collider experiments such as those at the LHC. Index Terms--Data acquisition, elementary particles, real time systems.

The fusion experiment Wendelstein 7-X demands synchronizing processes in many distributed technical components with an accuracy from milliseconds to nanoseconds. For this purpose a Trigger-Time-Event system (TTE system) was developed. Its main task is the synchronization of all control components and data acquisition systems. It allows time stamping, processing of trigger signals and event messages. The TTE system offers the possibility to program timing sequences and delays, logic combinations or conditions. After a description of the TTE system the task synchronization in the control system of WENDELSTEIN 7-X is discussed. A special software library (TimeLib) allows dealing with time related variables in a simple and comfortable manner. The efficiency of the synchronization system is exemplified. Index Terms--Control system, distributed real time system, fusion experiment, synchronization, timing system.

The Tore Supra tokamak is well adapted to sustain long-duration noninductive discharges using the lower hybrid (LH) heating and current drive as the main power source. In these conditions, the LH power deposition profile is strongly linked to the current density profile and can be deduced from the hard X-rays (HXRs) measurements which are produced by the suprathermal electrons generated by the absorption of the LH wave. The powerful HXR diagnostics that is present on Tore Supra has been recently connected to the real-time data network. The availability of the HXR measurements in real-time has allowed the development of an ad hoc algorithm for the real-time computation of the suprathermal electron local emission profile. Since the suprathermal electron local emission profile is well representative of the LH power deposition profile, this can be controlled in feedback (and thereby the current density profile as well). This paper illustrates the main features and real-time connections of the code developed to compute the suprathermal electron local emission profile, together with an explanation of the underlying physics and a description of the HXR diagnostics. Index Terms--Bessel functions, hard X-ray, local emission profile, real-time.

The control of rotating magnetic instabilities in a tokamak can be achieved by localized injection of radio-frequency (RF) driven current. Real-time detection of the radial location of the unstable 'magnetic islands' and of the RF power deposition has been achieved in a device designed, built, and tested on the FTU tokamak. Index Terms--Magnetic islands, radio frequency (RF), real-time control, tokamak.

This paper describes an architecture model for data acquisition systems based on compact PCI platforms. The aim is to increase real-time data processing capabilities in experimental environments such as nuclear fusion devices (e.g., ITER). The model has these features: 1) Real-time data acquisition: the system has been provided with real-time capabilities, developing specific data acquisition kernel modules under Linux and RTAI, using COMEDI project drivers; 2) Multiprocessor PCI eXtensions for Instrumentation (PXI) Architecture: the model makes possible to add one or more processing cards (in nonsystem slots) to each standard PXI chassis. Several real-time software modules have been developed to allow the communication between the PXI controller and the processing cards. This way the system performance is not restricted to the PXI controller's own performance. This model provides scalability to the system, adding or removing processing cards; 3) Real-time acquired data distribution: with this model it is possible to define how to distribute, in real-time, the data from all acquired signals in the system among the processing cards and the PXI controller; and 4) Dynamic Data Processing: a software platform has been developed to allow users to dynamically manage their own data processing algorithms in the system. This means that users can start, stop, modify, and replace their data processing algorithms without disrupting the data acquisition process or the rest of the data processing algorithms. Index Terms--Data acquisition, distributed data processing, real-time systems, thermonuclear fusion.

The Level-1 Calorimeter Trigger is a major part of the first stage of event selection for the ATLAS experiment at the LHC. It is a digital, pipelined system with several stages of processing, largely based on FPGAs, which perform programmable algorithms in parallel with a fixed latency to process about 300 Gbyte/s of input data. The real-time output consists of counts of different types of trigger objects and energy sums. Prototypes of all module types have been undergoing intensive testing before final production during 2005. Verification of their correct operation has been performed stand-alone and in the ATLAS test-beam at CERN. Results from these investigations will be presented, along with a description of the methodology used to perform the tests.

The need to control in real-time the plasma parameters in fusion devices leads to the development of algorithms requiring intensive computation and providing results on a few hundred microseconds. The present work's objective was the implementation of the current filaments method (CF) to model in real-time the ISTTOK plasma shape and position. The hardware used was the on site developed PCI-TR-256 hardware configurable module, which includes the latest technology in DSP and FPGA. The algorithm estimates the position of the plasma column and generates the control signals for the vertical magnetic field actuators. The main advantage of this system is to provide a digital approach to feedback plasma position control with similar cycle times to those of analog systems but allowing flexible, user defined, algorithms. Index Terms--Plasma position, real-time control, tokamak.

The Advanced Telecom Computing Architecture (ATCA), describes a high bandwidth, high connectivity, chassis based architecture designed principally to appeal to the telecommunications industry. The object of the exercise was to closely connect compute engines within the chassis to multiple user services brought in at the front panel. This maps closely to the needs of real time systems and the main points of the architecture are reviewed and discussed in that light. The performance of an ATCA backplane has been tested and measured using a Backplane Tester developed within a 10 Gb/s Ethernet switch project that was an early adopter of the ATCA standard. Some results from these tests are presented. Index Terms--ATCA, backplane, data acquisition, multiprocessor interconnection, real time systems.

A peer-to-peer (P2P)-based EAST Data System is being designed to provide data acquisition and analysis support for the EAST superconducting tokamak. Instead of transferring data to the servers, all collected data are stored in the data acquisition subsystems locally and the PC clients can access the raw data directly using the P2P architecture. Both online and offline systems are based on Napster-like P2P architecture. This allows the peer (PC) to act both as a client and as a server. A simulation-based method and a steady-state operational analysis technique are used for performance evaluation. These analyses show that the P2P technique can significantly reduce the completion time of raw data display and real-time processing on the online system, and raise the workload capacity and reduce the delay on the offline system. Index Terms--Client-server systems, data acquisition (DAQ), peer-to-peer systems, real-time analysis and display.

We have developed the test bed of control system for the Pohang Light Source (PLS) by using multimedia technologies. This test bed consists of three parts: a man-machine interface (MMI) with media data management, a data acquisition system, and a networking system. The MMI that contains specific application software is developed with an application program interface and a multimedia user interface toolkit. We use 100 Mbps Ethernet as a network system and a commercial database named ObjectStore to store data. Several VME systems with OS-9 operating system and PLC systems are used in the data acquisition layer. We present the result of test bed development.

A real-time computer control system has been developed and is used for the precise remote operation of the Pohang Light Source (PLS) 2-GeV storage ring. It consists of three layers of computer systems: console computer for operator interface, subsystem control computer (SCC) for front-end data processing, machine interface unit (MIU) for low-level data acquisition. The console computer is a Sun Microsystem's SPARCstation with UNIX. It uses X-Window/Motif for the GUI (graphic user interface) tool. The SCC acts as a front-end data processing between the console computer and the MIU. There are 24 MIUs placed in the storage ring building. The MIU is directly connected to individual machine components to do low-level data acquisition. The SCC and MIU are based on VMEbus standard and use Microware's OS-9 real-time operating system. Console computers and SCCs are connected through Ethernet (TCP/IP). SCCs and MIUs are connected through MIL-STD-1553B fieldbus. This paper presents general hardware and software structures of the control system.

It has been stated that an unbalanced data flow cannot be handled by blocking switches such as a barrel shifter. It is not true for a square switch, which has the same number of destination nodes as source nodes. However, if the switch is not square, a simple barrel shifter is not adequate. We have studied the minimal switch configuration for the event builder system in a BELLE experiment in KEK. The performance in the actual experiment was measured.

This paper describes the historical development, current state, and future plans of the computer control system of the National Superconducting Cyclotron Laboratory (NSCL). A proposal entitled, 'Proposal for a National Facility for Research with Heavy Ions using Coupled Superconducting Cyclotrons' was submitted to the National Science Foundation in September, 1976. The proposal was approved and the first cyclotron, the 'K500', came on-line with a limited experimental program in late 1982. The second cyclotron, the 'K1200' (formerly called the K800), and another limited experimental program came on-line in early 1988. In late 1990 the entire facility came on-line along with a full experimental program. Up to now, no formal paper has been submitted describing the computer control system for this facility; this paper seeks to fill that void.

The Data Acquisition for experiments at the KFA Juelich COoler SYnchrotron COSY is based on VME, FASTBUS, CAMAC, VICbus, Ethernet and UNIX workstations. Controller and master, equipped with CPUs, VME CPUs and workstations are formed to a distributed processor system, in software arranged by the object oriented Experiment Message Specification (EMS) protocol according to the server client connectivity. To perform the control of various experiment arrangements, composed of different number of crates with many embedded modules, a Control System, running on workstations was developed. Configurable setup of the frontend, run control, and distribution and decoding of event data are involved in the system. Experiment customizing is performed by ASCII files in an easy manner. The software is structured by dedicated clients with OSF/Motif user interface and access to the configurable experiment database. The design and state of the control system will be presented.

An object-oriented design for the distributed computer control system of the LEP/SPS rings is presented. A generic High Energy Physics design is presented that is inherited by a concrete design for the beam loss monitors subsystem.

A graphic-based realtime control system is developed and used for commissioning and operation of the PLS 2-GeV electron linac. The system has three layers of hierarchy; operator interface computer, supervisory control computer (SSC) for data processing, and device interface computer (DIC) for distributed data acquisition. The operator interface is based on the UNIX system with a graphic-based development system named RTworks. The SCC consists of three subsystems; modulators, magnet power supplies, and beam diagnostics. DICs attached to individual devices are placed in the 200-m linac building. There are altogether 23 VME CPUs and various I/Os in both SCC and DIC levels. The realtime operating system is OS-9. The major role of DICs is to control and to monitor individual devices upon operator's requests. The SCC updates variable database from DICs and conveys commands from the operator to DICs. SCCs and DICs are connected through a local area network to form a client/server system. Low-cost workstations are used for the operator interface. In order to have quick manipulation and easy understanding, we use intensive graphics for the control windows.