As high-speed networks make it easier to use distributed resources, it becomes increasingly common that applications and their data are not colocated. Users have traditionally addressed this problem by manually staging data to and from remote computers. We argue instead for a new remote I/O paradigm in which programs use familiar parallel I/O interfaces to access remote filesystems. In addition to simplifying remote execution, remote I/O can improve performance relative to staging by overlapping computation and data transfer or by reducing communication requirements. However, remote I/O also introduces new technical challenges in the areas of portability, performance, and integration with distributed computing systems. We propose techniques designed to address these challenges and describe a remote I/O library called RIO that we have developed to evaluate the effectiveness of these techniques. RIO addresses issues of portability by adopting the quasi-standard MPI-IO interface and by de...

Variability and unpredictability are probably the only well known characteristics of Internet traffic. These two aspects considerably hinder any serious attempt to model the Internet traffic behaviour. As a result, the dimensioning and the management of the underlying network resources are extremely difficult. New integrated services IP networks based on broadband transport technologies like ATM are not exceptions of this problem. Several issues, like network performance evaluation, applications quality of service requirements, users accounting, etc, over these networks are of increasing interest for both research community and network operation companies. Most of the works on Internet traffic behaviour over broadband networks rely on theoretical studies of the IP protocols and applications over the ATM layers, but they are in practice slightly underwritten by measured results. This leads to the necessity of detailed measurements of IP services behaviour over the ATM high speed backbones, where the different user applications traffic mix is fully outstanding.