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As processors become more powerful and clusters larger, users will exploit this increased power to progressively run larger and larger problems. Today's datasets in biology, physics or multimedia applications are huge and require high performance storage sub-systems. As a result, the hot spot of cluster computing is gradually moving from high performance computing to high performance IO. The solutions proposed by the parallel file-system community try to improve performance by working at the kernel level to enhance the regular IO design or by using a dedicated storage area network like Fiber Channel. We propose a new design to merge the communication network and the storage network at the best price. We have implemented it in OPIOM with the Myrinet interconnect. OPIOM moves data asynchronously from SCSI disks to the embedded memory of a Myrinet interface in order to send it to a remote node. This design presents attractive features: high performance and extremely low host overhead.

The existing SCSI parallel bus has been widely used in various multimedia applications. However, due to the unfair bus accesses the SCSI bus may not be able to fully utilize the potential aggregate throughput of disks. The number of disks that can be attached to the SCSI bus is limited, and link level fault tolerance is not provided. The serial storage interfaces such as Serial Storage Architecture (SSA) provide high data bandwidth, fair accesses, long transmission distance between adjacent devices (disks or hosts) and link level fault tolerance. The fairness algorithm of SSA ensures a fraction of data bandwidth to be allocated to each device. In this paper we would like to know whether SSA is a better alternative in supporting continuous media than SCSI. The scalability of a multimedia server is very important since the storage requirement may grow incrementally as more contents are created and stored. SSA in a shared-storage cluster environment also supports concurrent accesses by different hosts as long as their access paths are not overlapped. This feature is called spatial reuse. Therefore, the effective bandwidth over an SSA can be higher than the raw data bandwidth and the spatial reuse feature is critical to the scalability of a multimedia server. This feature is also included in FC-AL3 with a new mode called Multiple Circuit Mode (MCM). Using MCM, all devices can transfer data simultaneously without collision. In this paper we have investigated the scalability of shared-stroage clusters over an SSA environment.

CERN currently manages the largest data archive in the HEP domain; over 180PB of custodial data is archived across 7 enterprise tape libraries containing more than 25,000 tapes and using over 100 tape drives. Archival storage at this scale requires a leading edge monitoring infrastructure that acquires live and lifelong metrics from the hardware in order to assess and proactively identify potential drive and media level issues. In addition, protecting the privacy of sensitive archival data is becoming increasingly important and with it the need for a scalable, compute-efficient and cost-effective solution for data encryption. In this paper, we first describe the implementation of acquiring tape medium and drive related metrics reported by the SCSI interface and its integration with our monitoring system. We then address the incorporation of tape drive real-time encryption with dedicated drive hardware into the CASTOR [1] hierarchical mass storage system.

Increasing demand on data center and computer labs in Indonesia affected by the increasing number of users who use the computer for business or education. One of the main requirements that can not be separated from the use of a computer is a storage area in the form of a USB Flash Disk, External HD, HD to Internal HD for the need for a large-scale computer servers located in the data center, laboratory or computer network. Data storage space and data storage is growing with the advent of computer technology that gave rise to an alternative network storage of data such as DAS, NAS, FC, FCoE, and iSCSL iSCSI uses standard TCP / D? protocol over Ethernet to provide block-based storage. Today there are 2 main types of multiprotocol SCSI target in the industry LIO and COMSTAR which replaces the previous technology IET, SCST and STGT. LIO (Linux-iscsi.org) is the standard open source iSCSI target for shared storage space in Linux. LIO supports storage fabrics, the Fibre Channel (QLogic), FCoE, IEEE 1394, iSCSI, iSER (Mellanox InfiniBand), SRP (Mellanox InfiniBand), USB, vHost, and others.

This paper studies the effects of antenna correlation and co-channel interference (CCI) on a dual-hop amplify-and-forward (AF) relay network over Rayleigh fading channels, where the source and destination are equipped with a single antenna, while the relay has multiple antennas. By assuming that beamforming (BF) based on the available statistical channel state information (SCSI) is applied, we first obtain the output signal-to-interference-plus-noise ratio (SINR) of the considered dualhop AF transmission with CCI at the relay. Then, we derive the analytical expressions for the outage probability (OP) and average symbol error rate (ASER) of the AF relaying. Finally, computer simulations are provided to validate the analytical results and quantify the effects of antenna correlation and CCI on the system performance.

Participatory approaches involve stakeholder interaction but environmental agency employees engaged in participatory undertakings often lack training for interaction tasks. This study explored how district officers at the Soil Conservation Service of Iceland (SCSI) experienced and dealt with stakeholder interaction in participatory land restoration. We made semi-structured interviews with all district officers with at least 1-year experience; seven in total. A thematic content analysis revealed five challenges facing the officers in their interaction activities and seven strategies that they used to deal with these challenges. The core challenge was to establish and maintain contacts with farmers and other stakeholders as it enabled the SCSI to support and influence their land restoration practices. Other challenges were to: accomplish SCSI’s objectives; represent the SCSI and the government; have adequate skills, knowledge, and background; and deal with one's own emotions. Four of the strategies seemed to promote collaboration: create win–win scenarios; “go local”; direct and positive communication; and motivation and knowledge sharing. The other strategies: supportive district officer team; self-reliance and personal background; and self-control supported the officers in their interaction tasks. Factors undermining their collaboration efforts included insufficient time and other resources, an unsupportive organizational culture and a legal duty to assess the condition of vegetation cover on farmland. Increased resource allocation to the SCSI’s local operations, more attention to emotional issues, and efforts to develop a more flexible and learning organizational culture that supports collaboration could counteract these factors.

A single point of hardware failure in picture archiving and communication system (PACS) is at the PACS controller, or the main archive server. When it occurs, it renders the entire PACS inoperable and crippled until the problem is diagnosed and resolved. Many current PACS do not have a fault-tolerant design or adequate backup system for the main archive server due to several issues including cost. This paper describes a novel, portable, and scalable fault-tolerant PACS controller design that is affordable for most PACS implementations. Currently, most PACS controllers are based on UNIX servers. The UNIX server can be replaced by a specially designed Continuous Availability Server (CAS) consisting of three identical machines as the UNIX server that run the same operating system and application software simultaneously and independently. Hardware failure of any one or multiple components in a machine in the CAS, including the power supply, processors, SCSI ports, network ports, RAID controller, and disk controllers, was simulated. A series of clinical scenarios were performed while executing a simulated failure of the key hardware components within the CAS. No interruption of PACS data flow passing through the CAS was observed. Therefore, the result is a continuous availability server immune to a single point of hardware failure.

Digital libraries require not only high storage space capacity but also high performance storage systems which provide the fast accesses to the data. These requirements can not be efficiently supported with the traditional SCSI interfaces. Several serial storage interfaces have been proposed for constructing storage systems with high transfer bandwidth, large storage capacity, and fault tolerance feature. Among them, Serial Storage Architecture (SSA) and Fibre Channel-Arbitrated Loop (FC-AL) are considered as the next generation storage interfaces with broad industry support. Both technologies support simple cabling, long transmission distance, high data bandwidth, large capacity, fault tolerance, and fair sharing of link bandwidth. In this paper, a tutorial and a comparison of these two technologies are presented. The tutorial examines their interface specifications, transport protocols, fairness algorithms, and capabilities of fault tolerance. The comparison focuses on their protocol overhead, flow control, fairness algorithms, and fault tolerance. The paper also summarizes the recently proposed Aaron Proposal which incorporates features from both SSA and FC-AL and targets at merging these two technologies.

Fibre channel arbitrated loops offer a new approach to realizing high-speed storage interconnection networks. We describe an FC-AL topology and FC-AL protocols for storage networks. In particular, we describe channel arbitration, signaling and transmission protocols, and the fibre channel mapping protocol for SCSI. A simulation model of FC-AL storage networks is described. Performance results derived from the model are presented and are used to investigate the FC-AL storage network performance.

A new data analysis system has been developed with computer-controlled beam and sample positioning, video sample imaging, multiple large solid angle detectors for X-rays and gamma-rays, and surface barrier detectors for charged particles. The system uses the LabVIEW™ programming language allowing it to be easily ported between different computer operating systems. In the present configuration, digital signal processors are directly interfaced to a SCSI CAMAC controller. However, the modular software design permits the substitution of other hardware with LabVIEW-supported drivers. On-line displays of histogram and two-dimensional elemental map images provide a user-friendly data acquisition interface. Subregions of the two-dimensional maps may be selected interactively for detailed analysis or for subsequent scanning. Off-line data processing of archived data currently yields elemental maps, analyzed spectra and reconstructions of tomographic data.

In single crystal silicon (SCSi) MST devices, crystalline imperfection is recognized to favor failure. Defects are introduced by DRIE etching which is commonly used in SCSi structuring. However, thermal annealing improves the crystal quality. High resolution X-ray diffraction methods such as the rocking curve method and reciprocal space mapping can monitor crystalline imperfection in SCSi devices. A DRIE etched SCSi structure was built to study the crystal strain profile in dependence of the SCSi deformation by applying a mechanical force. Our investigations also include the numerical simulation of deformations.