Grid middleware refers to the collection of services (e.g. security, accounting, data access) that applications, users and resource providers need to operate effectively in a Grid environment.There are several major Grid middleware platforms available today.
OMII-Europe’s primary focus is on gLite, Globus and UNICORE because they are widely used in major European Grid projects. The interoperability that OMII-Europe is aiming to provide will benefit these projects greatly by allowing them to overcome the boundaries between Grids that run these different platforms. In addition to these three middleware stacks, OMII-Europe is also collaborating with OMII-UK and CROWN.
gLite is a complete set of middleware components developed within the EGEE project. gLite was initially developed to address the needs of two pilot applications in High-Energy Physics and in BioMedical computing, but is now used by over 20 applications. It is based on the pre-Web-Services Globus Toolkit 2.4 and many other technologies such as Condor, openssl, MyProxy and SRM. Some of the Services are Web Services based. gLite is available in open source form from CERN. While it is in itself a complete Grid solution, the more generic, Open Systems components being supplied through OMII-Europe’s partners are enhancing its ability to interoperate with other middleware platforms.
Globus is an open-source platform for Grid computing. It is a complete set of middleware components. Its pre-Web-Services releases, culminating in version 2.4 (properly referred to as GT2.4 or Globus Toolkit 2.4) is widely used in major projects in Europe as well as globally. The more recent Web Services version of Globus Toolkit (GT4) contains the whole of the pre-Web-Services components, for backward compatibility, thus allowing projects to evolve over time to a Web Services solution.
UNICORE (UNiform Interface to COmputing REsources) is also a set of middleware components developed within various European and German national projects. These components provide a service-oriented solution to Grid computing. UNICORE is deployed at many supercomputer sites, in particular those available through DEISA. Currently UNICORE primarily supports remote access to clusters and supercomputers, with its own abstraction from the concept of a job that enables it to be independent of the operating system and scheduler to which the job is submitted.
OMII-UK is a UK national project with bases in the University of Manchester, The University of Edinburgh and the University of Southampton. OMII-UK harvests Grid and e-Science software from across UK research projects and makes this software available, after quality improvements, via its repository. Components can be obtained separately or in bundles, to provide both clients and Web Services-based servers for constructing Grids and distributed e-Science applications. OMIIEurope is sourcing some of its components from OMII-UK.
CROWN (China Research and Development environment Over Wide-area Network) is a grid test bed that facilitates scientific activities in different disciplines. CROWN is a Web servicesbased toolkit (based on Globus Toolkit) which allows users to develop Web services on a remote resource running the CROWN software. The CROWN project was started in 2003. It aims to support large-scale resource sharing and coordinated problem solving by using service grid and other distributed computing technologies. A number of universities and institutes, such as Tsinghua University, Peking University, Chinese Academy of Sciences and Beihang University have joined CROWN. CROWN nodes are currently distributed across multiple worldwide sites, including UK, Australia and Hong Kong. In the future, CROWN will also be connected to other test-beds such as GLORIAD and PRAGMA.