[en] Short communication

[en] DESY is on the way of massive change in connecting and accessing Mass Storage systems. The main goal is to have full network connected storage devices combined with central network services which should be connected in case of store or retrieve of data

[en] An ever increasing number of computer systems-mainly PCs-require elaborated management strategies and tools. In the contribution to CHEP'01 the authors will present and discuss new concepts and developments concerning directory services and asset management. The authors will in particular report on first experiences with systems currently being implemented

[en] The article is about a piece of middle ware, allowing to convert a dump tape based Tertiary Storage System into a multi petabyte random access device with thousands of channels. Using typical caching mechanisms, the software optimizes the access to the underlying Storage System and makes better use of possibly expensive drives and robots or allows to integrate cheap and slow devices without introducing unacceptable performance degradation. In addition, using the standard NFS2 protocol, the dCache provides a unique view into the storage repository, hiding the physical location of the file data, cached or tape only. Bulk data transfer is supported through the kerberized FTP protocol and a C-API, providing the posix file access semantics. Dataset staging and disk space management is performed invisibly to the data clients. The project is a DESY, Fermilab joint effort to overcome limitations in the usage of tertiary storage resources common to many HEP labs. The distributed cache nodes may range from high performance SGI machines to commodity CERN Linux-IDE like file server models. Different cache nodes are assumed to have different affinities to particular storage groups or file sets. Affinities may be defined manually or are calculated by the dCache based on topology considerations. Cache nodes may have different disk space management policies to match the large variety of applications from raw data to user analysis data pools

[en] Data taking and analysis infrastructures in HEP (High Energy Physics) have evolved during many years to a well known problem domain. In contrast to HEP, third generation synchrotron light sources, existing and upcoming free electron lasers are confronted with an explosion in data rates driven primarily by recent developments in 2D pixel array detectors. The next generation of detectors will produce data in the region upwards of 50 Gbytes per second. At synchrotrons, data was traditionally taken away by users following data taking using portable media. This will clearly not scale at all.We present first experiences of our new architecture and underlying services based on results taken from the resumption of data taking in April 2015. Technology choices were undertaking over a period of twelve month. The work involved a close collaboration between central IT, beamline controls, and beamline support staff. In addition a cooperation was established between DESY IT and IBM to include industrial research and development experience and skills.Our approach integrates HPC technologies for storage systems and protocols. In particular, our solution uses a single file-system instance with a multiple protocol access, while operating within a single namespace. (paper)

[en] Published in summary form only

[en] Fission of ¹⁹⁷Au,²³²Th+838-MeV ³²S projectiles was studied by measuring fragment coincident neutrons. Neutron energy spectra were decomposed into preequilibrium, prescission, and postscission contributions with a constrained moving source analysis. Excitation energies deduced from the transferred linear momentum are consistent with calculations applying the Boltzmann master equation, and with an energy balance based upon the experimental neutron multiplicities and charged particles from evaporation calculations. The time scale of fission derived from the prescission neutron multiplicities extends from 5x10^-21 to 3x10^-20 s; it does not depend on the initial excitation energy, is about a factor of 2 longer for symmetric than for asymmetric fragmentations, and increases with the fissility of the primary reaction system. For all mass splits, the excitation energy left at scission is 50--60 MeV

[en] Data play a central role in most fields of science. In recent years, the amount of data from experiment, observation, and simulation has increased rapidly and data complexity has grown. Also, communities and shared storage have become geographically more distributed. Therefore, methods and techniques applied to scientific data need to be revised and partially be replaced, while keeping the community-specific needs in focus. The German Helmholtz Association project 'Large Scale Data Management and Analysis' (LSDMA) aims to maximize the efficiency of data life cycles in different research areas, ranging from high energy physics to systems biology. In its five Data Life Cycle Labs (DLCLs), data experts closely collaborate with the communities in joint research and development to optimize the respective data life cycle. In addition, the Data Services Integration Team (DSIT) provides data analysis tools and services which are common to several DLCLs. This paper describes the various activities within LSDMA and focuses on the work performed in the DLCLs.

[en] Modern science is most often driven by data. Improvements in state-of-the-art technologies and methods in many scientific disciplines lead not only to increasing data rates, but also to the need to improve or even completely overhaul their data life cycle management.Communities usually face two kinds of challenges: generic ones like federated authorization and authentication infrastructures and data preservation, and ones that are specific to their community and their respective data life cycle. In practice, the specific requirements often hinder the use of generic tools and methods.The German Helmholtz Association project ’’Large-Scale Data Management and Analysis” (LSDMA) addresses both challenges: its five Data Life Cycle Labs (DLCLs) closely collaborate with communities in joint research and development to optimize the communities data life cycle management, while its Data Services Integration Team (DSIT) provides generic data tools and services.We present most recent developments and results from the DLCLs covering communities ranging from heavy ion physics and photon science to high-throughput microscopy, and from DSIT. (paper)

[en] Published in summary form only