A practical large scale/high speed data distribution system using 8 mm libraries

Eight mm tape libraries are known primarily for their small size, large storage capacity, and low cost. However, many applications require an additional attribute which, heretofore, has been lacking -- high transfer rate. Transfer rate is particularly important in a large scale data distribution environment -- an environment in which 8 mm tape should play a very important role. Data distribution is a natural application for 8 mm for several reasons: most large laboratories have access to 8 mm tape drives, 8 mm tapes are upwardly compatible, 8 mm media are very inexpensive, 8 mm media are light weight (important for shipping purposes), and 8 mm media densely pack data (5 gigabytes now and 15 gigabytes on the horizon). If the transfer rate issue were resolved, 8 mm could offer a good solution to the data distribution problem. To that end Exabyte has analyzed four ways to increase its transfer rate: native drive transfer rate increases, data compression at the drive level, tape striping, and homogeneous drive utilization. Exabyte is actively pursuing native drive transfer rate increases and drive level data compression. However, for non-transmitted bulk data applications (which include data distribution) the other two methods (tape striping and homogeneous drive utilization) hold promise

Robo-line storage: Low latency, high capacity storage systems over geographically distributed networks

Rapid advances in high performance computing are making possible more complete and accurate computer-based modeling of complex physical phenomena, such as weather front interactions, dynamics of chemical reactions, numerical aerodynamic analysis of airframes, and ocean-land-atmosphere interactions. Many of these 'grand challenge' applications are as demanding of the underlying storage system, in terms of their capacity and bandwidth requirements, as they are on the computational power of the processor. A global view of the Earth's ocean chlorophyll and land vegetation requires over 2 terabytes of raw satellite image data. In this paper, we describe our planned research program in high capacity, high bandwidth storage systems. The project has four overall goals. First, we will examine new methods for high capacity storage systems, made possible by low cost, small form factor magnetic and optical tape systems. Second, access to the storage system will be low latency and high bandwidth. To achieve this, we must interleave data transfer at all levels of the storage system, including devices, controllers, servers, and communications links. Latency will be reduced by extensive caching throughout the storage hierarchy. Third, we will provide effective management of a storage hierarchy, extending the techniques already developed for the Log Structured File System. Finally, we will construct a protototype high capacity file server, suitable for use on the National Research and Education Network (NREN). Such research must be a Cornerstone of any coherent program in high performance computing and communications

Introduction to Multiprocessor I/O Architecture

The computational performance of multiprocessors continues to improve by leaps and bounds, fueled in part by rapid improvements in processor and interconnection technology. I/O performance thus becomes ever more critical, to avoid becoming the bottleneck of system performance. In this paper we provide an introduction to I/O architectural issues in multiprocessors, with a focus on disk subsystems. While we discuss examples from actual architectures and provide pointers to interesting research in the literature, we do not attempt to provide a comprehensive survey. We concentrate on a study of the architectural design issues, and the effects of different design alternatives

Queuing Models of Tertiary Storage

Large scale scientific projects generate and use large amounts of data. For example, the NASA Earth Observation System Data and Information System (EOSDIS) project is expected to archive one petabyte per year of raw satellite data. This data is made automatically available for processing into higher level data products and for dissemination to the scientific community. Such large volumes of data can only be stored in robotic storage libraries (RSL's) for near-line access. A characteristic of RSL's is the use of a robot arm that transfers media between a storage rack and the read/write drives, thus multiplying the capacity of the system. The performance of the RSL's can be a critical limiting factor for the performance of the archive system. However, the many interacting components of an RSL make a performance analysis difficult. In addition, different RSL components can have widely varying performance characteristics. This paper describes our work to develop performance models of an RSL in isolation. Next we show how the RSL model can be incorporated into a queuing network model. We use the models to make some example performance studies of archive systems. The models described in this paper, developed for the NASA EODIS project, are implemented in C with a well defined interface. The source code, accompanying documentation, and also sample JAVA applets are available at: http://www.cis.ufl.edu/~ted

Extending the Life of Paint and Reflective Markers by Using Partial Rubber Plow Blades

Winter roadway maintenance in Indiana typically involves the removal of snow and ice from the roadway with metal plow blades. The interaction of the wearable metal portion of the plow and the roadway causes damage to raised pavement markers (RPMs) and painted line markings. Partial rubber snow plow blades (PRPBs) are currently available as an alternative to full metal blades. The purpose of this project was to conduct a limited study to evaluate the decrease in damage to the RPMs and pavement markings, and rate the snow removal performance of the PRPB verses the traditional steel carbide blade. Overall there was no solid evidence supporting the premise that the PRPB equipped with rubber wingtips damaged RPMs and striping less than the traditional plow equipped with a steel cutting edge. Overall the PRPB did not perform nearly as well as the steel blade based on the opinions of INDOT plow operators

Goddard Conference on Mass Storage Systems and Technologies, Volume 1

Copies of nearly all of the technical papers and viewgraphs presented at the Goddard Conference on Mass Storage Systems and Technologies held in Sep. 1992 are included. The conference served as an informational exchange forum for topics primarily relating to the ingestion and management of massive amounts of data and the attendant problems (data ingestion rates now approach the order of terabytes per day). Discussion topics include the IEEE Mass Storage System Reference Model, data archiving standards, high-performance storage devices, magnetic and magneto-optic storage systems, magnetic and optical recording technologies, high-performance helical scan recording systems, and low end helical scan tape drives. Additional topics addressed the evolution of the identifiable unit for processing purposes as data ingestion rates increase dramatically, and the present state of the art in mass storage technology

Mineralogical mapping using airborne imaging spectrometry data

With the development of airborne, high spectral resolution imaging spectrometers, we now have a tool, that allows us to examine surface materials with enough spectral detail to identify them. Identification is based on the analysis of position and shape of absorption features in the material spectra in the visible and infrared (0.4µm to 2.5µm). These absorption features are caused by the interaction of Electro-Magnetic Radiation (EMR) with the atoms and molecules of the surface material. Airborne data were collected to evaluate these new high spectral resolution systems. The data quality was assessed prior to processing and analysis and several problems were noted for each data set (striping, geometric distortion, etc.). These problems required some preparation of the data. After data preparation, data processing methods were evaluated, concentrating primarily on the log residuals and hull quotients methods. The processing steps convert the data to a form suitable for analysis. The data was analysed using the Spectral Analysis Manager (SPAM) package, developed by JPL. Two Imaging spectrometers were evaluated. The AIS - 1 instrument was flown over an area in Queensland, Australia. Ground data and laboratory work confirmed the presence of anomalous areas detected by the instrument. The data quality was poor and only basic classification of the data was possible. Anomalies were classed as "GREEN VEGETATION", "DRY VEGETATION", "CLAY" or "CARBONATE" based on the position of the major absorptions observed. The second instrument, the GER - II was flown over an area of Nevada, USA. Ground data and laboratory work confirmed the presence of the anomalies detected by the instrument. The data quality was somewhat better. Identification of sericite, dolomite and illite was possible. However, most of the area could still only be classed in the broad groupings listed above. To conclude, the effectiveness of identification is limited to a large degree by the poor data quality. If the data quality can be improved, techniques can be applied to automatically locate and identify material spectra, from the airborne data alone

On-board multispectral classification study

The factors relating to onboard multispectral classification were investigated. The functions implemented in ground-based processing systems for current Earth observation sensors were reviewed. The Multispectral Scanner, Thematic Mapper, Return Beam Vidicon, and Heat Capacity Mapper were studied. The concept of classification was reviewed and extended from the ground-based image processing functions to an onboard system capable of multispectral classification. Eight different onboard configurations, each with varying amounts of ground-spacecraft interaction, were evaluated. Each configuration was evaluated in terms of turnaround time, onboard processing and storage requirements, geometric and classification accuracy, onboard complexity, and ancillary data required from the ground

An integrated software system for geometric correction of LANDSAT MSS imagery

A system for geometrically correcting LANDSAT MSS imagery includes all phases of processing, from receiving a raw computer compatible tape (CCT) to the generation of a corrected CCT (or UTM mosaic). The system comprises modules for: (1) control of the processing flow; (2) calculation of satellite ephemeris and attitude parameters, (3) generation of uncorrected files from raw CCT data; (4) creation, management and maintenance of a ground control point library; (5) determination of the image correction equations, using attitude and ephemeris parameters and existing ground control points; (6) generation of corrected LANDSAT file, using the equations determined beforehand; (7) union of LANDSAT scenes to produce and UTM mosaic; and (8) generation of output tape, in super-structure format