The grid networks have developed for more then 10 years. While the number of grid application field has been grown, the middleware solutions have also became more different. The developers always tried to design the produced protocol or program to supply their goals with the highest productivity. Therefore the basically Globus based middleware in spite of the common origin diverged from each other. The standardization efforts conducted today also helps different grid middleware solutions to inter-operate with each other on the application level.

We are also emphasizing in our work in the KnowARC project to participate the standardization work in Europe and to follow the existing ones. There is also an extraordinary client library as a part of the developed ARC middleware. Such application can be developed with the help of this library that can control and use more than one middleware via different interfaces without any kind of extra user interaction in a very transparent way. These features can be achieved by two most important components of the library.

The library has a modular structure and the different middleware can be accessed through these component. Naturally, choosing the proper module and communication in different interfaces are done hidden from the user in a completely transparent way.

Among others a job description is needed for running a job in a grid system. This document contains information about the job, the requested resources and the command to execute. These descriptions can also have different syntax and semantic in case of the different middleware. We have designed and implemented a job description converter for this purpose that is able to rebuild (of course in a transparent way) the job relevant information in a format accepted by the middleware where the job is sent.

In my presentation, I would like to present the ARC client library which can cope with numerous grid middleware solutions and able to handle the classic ARC, the new generation ARC or even the gLite resources in the same time in a transparent way.