Online Performance Monitoring of the Third ALICE Data Challenge (ADC III)

The ALICE data acquisition system has been designed for a maximum bandwidth of 2.5 GB/s for event building and of 1.25 GB/s for mass storage. In order to attain a gradual integration of the overall computing infrastructure, the present hardware components and software prototypes are tested during regular ALICE data challenges. The third one (ADC III) took place from January to March 2001 as a joint effort between the ALICE online/offine team and the CERN IT division. The main goal of this data challenge was to achieve a stable 300 MB/s throughput in the event building network and a 100 MB/s throughput to CASTOR over periods of a few days. Performance monitoring was another goal of this exercise, where a prototype (dateStat ) was developed to collect and display statistics. In this paper we will introduce this online monitoring system and report on some of the obtained results. It is structured in three parts: (1) An overview will be given on the testbed hardware, the software running on it, and the data flow. (2) The architecture of the monitoring system will be described, which consists of a set of C programs, Perl/gnuplot/CGI scripts ,and a MySQL database. It allows to measure individual/aggregate data rates,collected data volumes, and CPU loads. All these values can be visualized on web pages both on a run-by-run and global basis. (3) Various plots will be shown to illustrate the usefulness of this online monitoring system and to document the outcome of the ADC III. Finally, some ideas will be pointed out how to advance dateStat

The Usage of ROOT for Online Monitoring in the ALICE DATE System

Presentation for CHEP2000Data Acquisition systems for HEP applications need constant monitoring (online and offline) of their data streams to accomplish several tasks: quality checking, tuning, statistics, pre-analysis. Monitoring tasks can and should use the same tools as data analysis products (conventions, libraries, environments) to reduce training, installation, development and support efforts and -at the same time - to strengthen the liaison between the online and the offline worlds. The ALICE DATE Data Acquisition system available today for R&D and for test beams is fully integrated with the ROOT environment. A simple DAQ-oriented approach and a more complex OO-based model have been developed to allow a variety of programming paradigms and to validate the complete life cycle of monitoring tools, both for online and offline environments

PCI Based Read-out Receiver Card in the ALICE DAQ System

The Detector Data Link (DDL) is the high-speed optical link for the ALICE experiment. This link shall transfer the data coming from the detectors at 100 MB/s rate. The main components of the link have been developed: the destination Interface Unit (DIU), the Source Interface Unit (SIU) and the Read-out Receiver Card (RORC). The first RORC version is based on the VME bus. The performance tests show that the maximum VME bandwidth could be reached. Meanwhile the PCI bus became very popular and is used in many platforms. The development of a PCI-based version has been started. The document describes the prototype version in three sections. An overview explains the main purpose of the card: to provide an interface between the DDL and the PCI bus. Acting as a 32bit/33MHz PCI master the card is able to write or read directly to or from the system memory from or to the DDL, respectively. Beside these functions the card can also be used as an autonomous data generator. The card has been designed to be well adapted to applications, which require small software overhead such the high-speed data acquisition systems. The implementation of the firmware will be presented. For the logic design we are using VHDL and schematic draw. Software library routines were written in C and are available on Linux OS. The results of performance measurements will be available to allow the comparison between the VME-RORC and PCI-RORC. In the conclusion the future plans and the idea of the improved (64bit/66MHz) PCI-RORC will be shown

The ALICE Data Challenges

Since 1998, the ALICE experiment and the CERN/IT division have jointly executed several large-scale high throughput distributed computing exercises: the ALICE data challenges. The goals of these regular exercises are to test hardware and software components of the data acquisition and computing systems in realistic conditions and to execute an early integration of the overall ALICE computing infrastructure. This paper reports on the third ALICE Data Challenge (ADC III) that has been performed at CERN from January to March 2001. The data used during the ADC III are simulated physics raw data of the ALICE TPC, produced with the ALICE simulation program AliRoot. The data acquisition was based on the ALICE online framework called the ALICE Data Acquisition Test Environment (DATE) system. The data after event building were then formatted with the ROOT I/O package and a data catalogue based on MySQL was established. The Mass Storage System used during ADC III is CASTOR. Different software tools have been used to monitor the performances. DATE has demonstrated performances of more than 500 MByte/s. An aggregate data throughput of 85 MByte/s was sustained in CASTOR over several days. The total collected data amounts to 100 TBytes in 100,000 files

Challenging the challenge: handling data in the Gigabit/s range

The ALICE experiment at CERN will propose unprecedented requirements for event building and data recording. New technologies will be adopted as well as ad-hoc frameworks, from the acquisition of experimental data up to the transfer onto permanent media and its later access. These issues justify a careful, in-depth planning and preparation. The ALICE Data Challenge is a very important step of this development process where simulated detector data is moved from dummy data sources up to the recording media using processing elements and data-paths as realistic as possible. We will review herein the current status of past, present and future ALICE Data Challenges, with particular reference to the sessions held in 2002 when - for the first time - streams worth one week of ALICE data were recorded onto tape media at sustained rates exceeding 300 MB/s.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics (CHEP03), La Jolla, Ca, USA, March 2003, 9 pages, PDF. PSN MOGT00

The ALICE DAQ: Current Status and Future Challenges

Proposal of abstract for CHEP2000The ALICE DAQ system has been designed to support an aggregate eventr building bandwidth of up to 2.5 GByte/s and a storage capability o fup to 1.25 GByte/s to mass storage.A general framework called the ALICE Data Acquisition Test Environment (DATE) system has been developed as a basis for prototyping the components of the DAQ. DATE supports a wide spectrum of configurations from simple systems to more complex systems with multiple detectors and multiple event builders.Prototypes of several key components of the ALICE DAQ have been developed and integrated with the DATE system, such as the ALICE Detector Data Link, the online data monitoring from ROOT and the interface to the Mass Storage systems. Combined tests of several of these components are pursued during the ALICE Data Challenges.The architecture of the ALICE DAQ system will be presented together with the current status of the different prototypes. The recent addition of a Transition Radiation Detector (TRD) to ALICE has required a revision of the requirements and the architecture of the DAQ. This will allow a higher level of data selection. These new opportunities and implementation challenges will also be presented

Modelling and Operational Effectiveness Evaluation for Integrated Gun and Missile Anti-aircraft System

弹炮结合防空武器系统是随着空袭与反空袭防空作战发展而产生的一种综合防空武器系统，是防空作战武器装备体系的重要组成部分。该系统由中低空地对空导弹和小口径高炮两种防空武器按一定的结合方式组合而成，二者组合可以发挥导弹中高空毁伤率高、高炮低空火力猛、抗干扰能力强等优势，能够在防空作战时取得更好的作战效果。 对防空武器系统的发展论证需要采用定性分析与定量分析相结合的科学方法，寻找防空武器系统作战能力的差距，分析影响防空武器系统效能的关键因素，进而研究防空武器装备建设重点和发展方向及作战使用原则。弹炮结合防空武器系统的研究包括很多方面，本文主要研究弹炮结合防空武器系统的作战模型和效能评估技术。论文分析...With the development of modern air raid and anti-air raid in warfare，integrated anti-aircrafts gun and missile system，as one of important components of air defence equipment system，has become a comprehensive air defence weapon system. This system is made up of two air-defence weapons: mid-low air space from earth to air missile, and small-diameter gun. And these two weapons are integrated in speci...学位：工学硕士院系专业：信息科学与技术学院自动化系_系统工程学号：20033102

Alignment of the ALICE Inner Tracking System with cosmic-ray tracks

37 pages, 15 figures, revised version, accepted by JINSTALICE (A Large Ion Collider Experiment) is the LHC (Large Hadron Collider) experiment devoted to investigating the strongly interacting matter created in nucleus-nucleus collisions at the LHC energies. The ALICE ITS, Inner Tracking System, consists of six cylindrical layers of silicon detectors with three different technologies; in the outward direction: two layers of pixel detectors, two layers each of drift, and strip detectors. The number of parameters to be determined in the spatial alignment of the 2198 sensor modules of the ITS is about 13,000. The target alignment precision is well below 10 micron in some cases (pixels). The sources of alignment information include survey measurements, and the reconstructed tracks from cosmic rays and from proton-proton collisions. The main track-based alignment method uses the Millepede global approach. An iterative local method was developed and used as well. We present the results obtained for the ITS alignment using about 10^5 charged tracks from cosmic rays that have been collected during summer 2008, with the ALICE solenoidal magnet switched off.Peer reviewe