Study on R&D of Computing System for Collider Experiments

从硬件和软件两个方面对大型强子对撞机实验的计算技术进行了研究。具体而言，以下三个项目是通过CERN和us的各种合作者进行研究的。实时数据采集在高能强子对撞机大型探测器中，数据采集的主要问题是探测器中多个数据源传输到实时计算系统的总数据容量。灵活、高速的数据流控制是该系统的关键。在这个项目中，我们与欧洲核子研究中心和费米实验室合作。研究可能的解决方案。提出了采用串行交换系统的“全局交通控制系统”。另一方面，欧洲核子研究中心小组已经研究了一种可能使用的商业ATM交换系统，即“自路由系统”。利用计算机程序对两种系统进行了仿真。这些结果已在1994年10月的讲习班上提出。如果没有系统的全局流量控制，更多的系统是不适合这个应用的。大数据处理的计算机系统研究了大数据的存储和访问。以磁带为基础的存储系统在存储数百兆字节的大容量数据方面具有广阔的应用前景。对现有技术的调查表明，螺旋扫描型磁带系统是适用的。然而，在计算机系统设计中，对如此大的数据文件的访问方法是数据处理的关键。CERN和KEK研究了不同的实验数据获取模式。目前，该系统正在欧洲核子研究中心和KEK.3进行测试。程序库开发的国际合作在高能物理实验的大型国际合作中，各种软件开发必须由分散在世界各地的许多合作者完成。面向对象软件设计与开发的新技术应运而生。采用对象建模技术（OMT）方法，研究了应用广泛的探测器仿真程序GEANT的重新设计过程。对研究结果进行了评价，以促进大型软件在该技术下的再工程发展。少

Computing technology for the large hadron collider experiment has been surveyed and investigated from both points of hardware and software. Particularlly, the following three items were studyed through various collaborators in CERN and US.1. Real-time Data AcquisitionMajor concern on the data acquisition in the large detector of hadron collider at ultra-high energy is the total data capacity to be transpfered from many data sources in the detector to real time computing system. The flexible and high speed data flow control is essential for the system. In this project, we have collaborated with CERN and Fermi Lab. to study the possible solution. We proposed "Global trafic control system" with serial switching system. On the other hand, CERN group has been studyed a possible use of commercial ATM switch system which is "Self routing system". The simulation of the both system were carried out using computer program. These results has been presented in the workshop Oct. 1994. "Self routing … More system is not adequat for this application without any global traffic control of the system.2. Computer System for Large Data ProcessingLarge data storage and its access have been studied. Magnetic tape based storage system is promising for large volum data order of hundreds tela bytes. A suvey of the current technology has shown helical scan type tape systems applicable. However, access method to such large data file is key for data processing in the design of the computer system. CERN and KEK investigated various access pattern to the experimental data. Currently hialachical storage management system is under implementation for test at CERN and KEK.3. Internation collaboration for development of program librariesIn a large international collaboration for high energy physics experiments, various software development must be done by a number of collaborators scattered in the world. New software technology of object oriented software design and development has been studied to cope with this situation. Re-design process of detector simulation program : GEANT which is widely used were investigated following the method of OMT (Object Modeling Technique). The result of study has been evaluated to promote re-engineering of the large software for the future development under this technology. Less