Common use of ARC Clause in Contracts

ARC. ARC is designed and implemented as a reliable, efficient, highly portable and easy-to handle middleware. It is optimized for serial data-intensive computational tasks, such that input and output data manipulation is considered an integral part of a computing service. This significantly optimizes CPU utilization, automatically allows for data caching, enables optimal bandwidth usage, and minimizes the risk of accidental distributed denial of service attacks. A key concept is the absence of a single point of failure. Combined with a stateful implementation of services, this ensures high stability of the system. Another feature of ARC is clear separation between the local batch systems and the Grid: the clear interface allows integration of any batch system via plug- ins. The middleware heavily relies on the distributed, multi-rooted dynamic information system that contributes to the overall redundancy and scalability of the infrastructure. Information system design allows encapsulating resource discovery, matchmaking and brokering in the client, avoiding thus a typical single point of failure. ARC client tools are implemented on top of a powerful API, which facilitates development of application-specific clients, portals or even workload or workflow management systems. Another key aspect of ARC is its non-intrusiveness with respect to the underlying resources: it deploys as a comparatively thin layer, with software installation only on the front-end. It can thus co-exist with any other middleware or setup. Not only is ARC light-weight, it is also easy to maintain and operate: it includes support for retries of transfer failures, transparent downtime handling, support for memory and CPU time limits, and all configuration is done through only one file. For historical interoperability reasons, ARC security largely relies on X509 proxies, though its recently upgraded security framework allows for virtually any X509-based solution and other widely used technologies, such as Shibboleth. The provided credential client utility can be used to interoperate with third-party services, such as the Virtual Organization Management Service (VOMS) and MyProxy.