Grid computing can help to promote high-performance computing at a low overall cost by encouraging research centers to share their resources. However, research staff usually finds it quite hard to use Grids effectively, due to the need of installing and managing new Grid software. Thus, Grid portals are created, making it easier to take advantage of the full capability of the Grid, favoring in this way its use. The goal of this paper is to describe the process of design and implementation of a Grid Portal with the aim of both supporting distributed high-performance resources and make its use by researchers as transparent as possible. This portal uses standard Grid and Web technologies. We have designed the portal so that it can be adapted to different existing Grid infrastructures, based on the Globus Toolkit, and new functionalities can be easily added. The first prototype of the portal has been tested on an experimental Grid platform, and we present encouraging experiences carried out there.

This paper presents CPPC (Controller/Precompiler for Portable Checkpointing), a checkpointing tool designed for heterogeneous clusters and Grid infrastructures through the use of portable protocols, portable checkpoint files and portable code. It works at variable level being user-directed, thus generating small checkpoint files. It allows parallel processes to checkpoint independently, without runtime coordination or message-logging. Consistency is achieved at restart time by negotiating the restart point. A directive-based checkpointing precompiler has also been implemented to ease up user's effort. CPPC was designed to work with parallel MPI programs, though it can be used with sequential ones, and easily extended to parallel programs written using different message-passing libraries, due to its highly modular design. Experimental results are shown using CPPC with different test applications.