ARC Middleware

The choice of middleware(s) supported by NDGF is a balance between their applicability to requirements of the user groups supported by NDGF, and the amount of work needed to support more than one middleware.

NDGF currently supports the NorduGrid Advanced Resource Connector (ARC) middleware. The choice of ARC is based on
the following properties of the software:

• The services needed at scientific computation centres can be installed on top of a number of different Linux distributions.
• The installation is comparatively non-intrusive requering only installation of a front-end server which can have limited access to the rest of the system.
• Client software is expected to be made available for operating systems other than Linux.
• NDGF has established a close and good working relation with the NorduGrid collaboration and the KnowARC project, allowing NDGF to easily contribute to the development of ARC and to influcence the general direction taken in the development of the software.

ARC provides a reliable implementation of the fundamental Grid services, such as information services, resource discovery and monitoring, job submission and management, brokering and data
management and resource management. Most of these services are provided through the security layer of the GSI@. The middleware builds upon standard Open Source solutions like the OpenLDAP, OpenSSL, SASL and Globus Toolkit\textregistered (GT) libraries. All the external sofware is provided in the download area and the complete list of external software dependencies can be found here. NorduGrid provides innovative solutions essential for a production quality middleware: the Grid Manager, gridftpd (the ARC/NorduGrid GridFTP server), the information model and providers (NorduGrid schema), User Interface and broker (a "personal" broker integrated into the user interface), extended
Resource Specification Language (xRSL), and the monitoring system.