University of Tennessee-Knoxville (UTK)
Netlib and the National High-performance Software Exchange
The Netlib software repository contains freely available software, documents, and databases of interest to the numerical, scientific computing, and other research communities. The repository is maintained by Lucent Technologies, by the University of Tennessee and Oak Ridge National Laboratory, and by colleagues world-wide. Many sites around the world mirror the collection and are automatically synchronized to provide reliable and efficient service to the global community through a variety of access mechanisms. Netlib differs from many other publicly available software repositories in that the collection is moderated by an editorial board and is widely recognized to be of high quality. Software packages are included in the main numerical analysis areas of linear systems, eigenvalue problems, quadrature, nonlinear equations, differential equations, and optimization. In addition to the traditional numerical analysis areas, Netlib also contains computer graphics and computational geometry software and parallel processing tools. The collection changes gradually as new software packages and routines are added and as existing packages are updated. The mathematical software portion of Netlib is classified using the Guide to Mathematical Software (GAMS) system, a tree-structured taxonomy of mathematical and statistical problems.
The National High-performance Software Exchange (NHSE) is a distributed collection of metadata about software, documents, data, and information of interest to the high performance and parallel computing community. The NHSE actively promotes software sharing and reuse within and across federal high-performance computing programs. The NHSE facilitates the development of discipline-oriented software and document repositories. Existing NHSE repositories include HPC-Netlib (high performance branch of Netlib), Parallel Tools Library (PTLIB), Benchweb (a repository of benchmark information and software), and a number of discipline-oriented repositories at the Department of Defense Major Shared Resource Centers, NSF PACI sites, and NASA HPCC sites. See http://www.nhse.org/software.html for a complete list which includes such areas as computational chemistry, signal and image processing, and parallel tools. The NHSE maintains the NHSE Software Catalog which is a virtual catalog that imports the contents of several discipline-oriented repositories to provide a single browsing and searching interface. The NHSE Technical Team has developed a software toolkit for setting up and maintaining a software repository. This toolkit, called Repository in a Box (RIB), enables organizations to develop and administrate their own software repositories and to interoperate by sharing metadata with other RIB repositories.
Number of items, format and total size
At this date (November 1999), the Netlib collection contains over 58,000 files of software and documents organized into around 200 top-level directories, taking up a total of approximately 1.6 gigabytes of disk space. There have been over 57 million download requests to Netlib since its inception in 1985. Most of the software is written in Fortran but programs in other languages, such as C and C++, are also available. Software is provided as compressed tar files, and for some collections, as individual source files. When individual source files are downloaded, the user can request that the dependent files necessary to build a complete program also be included. The number of Netlib servers has also grown from the original two at Lucent and UTK, to servers in Norway, the United Kingdom, Germany, Australia, Japan, and Taiwan. A mirroring mechanism keeps the repository contents at the different sites consistent on a daily basis and automatically picks up new material from distributed editorial sites. Each server is the master for a particular subset of the collection, which is then mirrored by all the other servers. The original e-mail interface to Netlib is still available, although its use has decreased. Most access to Netlib today is through the Web interface which provides both browsing of the directory structure and searching by keyword or the GAMS classification scheme.
Being a virtual catalog, the NHSE does not contain files itself but is instead an interface to a collection of autonomously maintained software metadata repositories. The RIB toolkit is built on top of an underlying relational database, but interoperability is provided by means of XML. Queries to RIB repositories and results returned are in XML format. RIB repositories use an extensible entity-relationship data model based on the Basic Interoperability Data Model (BIDM) which is an IEEE standard for software cataloging on the Internet. The BIDM specifies a minimal set of entities, attributes, and relationships considered necessary for successful interoperation and exchange of software metadata. In addition to providing access to users from their Web browsers, RIB provides an Application Programmer's Interface (API) to enable interoperation between RIB and other Web-based repositories and tools.
Restrictions on access
Each software contributor to Netlib defines his or her own access restrictions. Each participating organization in the NHSE defines its own access restrictions. Information about access restrictions is intended to be provided by the DistributionStatement attribute in the BIDM and by the Intellectual Property Rights extension to the BIDM.
Further information
For further information about this testbed, see: http://www.netlib.org/ and http://www.nhse.org/.
Researchers who wish to make use of this testbed should contact: Paul McMahan at University of Tennessee-Knoxville.
prepared by Shirley V. Browne
last modified 11/9/99