No abstract

The Internet, best known by most users as the World-WideWeb, continues to expand at an amazing pace. We propose a new infrastructure to harness the combined resources, such as CPU cycles or disk storage, and make them available to everyone interested. This infrastructure has the potential for solving parallel supercomputing applications involving thousands of cooperating components. Our approach is based on recent advances in Internet connectivity and the implementation of safe distributed computing embodied in languages such as Java.We developed a prototype of a global computing infrastructure, called SuperWeb, that consists of hosts, brokers and clients. Hosts register a fraction of their computing resources (CPU time, memory, bandwidth, disk space) with resource brokers. Client computations are then mapped by the broker onto the registered resources. We examine an economic model for trading computing resources, and discuss several technical challenges associated with such a global computing environment.

The Internet, in particular the World Wide Web, continues to expand at an amazing pace. We propose a new infrastructure, SuperWeb, to harness global resources, such as CPU cycles or disk storage, and make them available to every user on the Internet. SuperWeb has the potential for solving parallel supercomputing applications involving thousands of co‐operating components on the Internet. However, we anticipate that initial implementations will be used inside large organizations with large heterogeneous intranets. Our approach is based on recent advances in Internet connectivity and the implementation of safe distributed computing realized by languages such as Java. Our SuperWeb prototype consists of brokers, clients and hosts. Hosts register a fraction of their computing resources (CPU time, memory, bandwidth, disk space) with resource brokers. Clients submit tasks that need to be executed. The broker maps client computations onto the registered hosts. We examine an economic model for trading computing resources, and discuss several technical challenges associated with such a global computing environment. © 1997 John Wiley & Sons, Ltd.

In this article we show how to extend a wide range of functionality of standard operating systems completely at the user level. Our approach works by intercepting selected system calls at the user level, using tracing facilities such as the /proc file system provided by many Unix operating systems. The behavior of some intercepted system calls is then modified to implement new functionality. This approach does not require any relinking or recompilation of existing applications. In fact, the extensions can even be dynamically "installed" into already running processes. The extensions work completely at the user level and install without system administrator assistance. Individual users can choose what extensions to run, in effect creating a personalized operating system view for themselves. We used this approach to implement a global file system, called Ufo, which allows users to treat remote files exactly as if they were local. Currently, Ufo supports file access through the FTP and HTTP protocols and allows new protocols to be plugged in. While several other projects have implemented global file system abstractions, they all require either changes to the operating system or modifications to standard libraries. The article gives a detailed performance analysis of our approach to extending the OS and establishes that Ufo introduces acceptable overhead for common applications even though intercepting individual system calls incurs a high cost.

Fast and efficient communication is one of the most important requirements in today's multicomputers. When reaching a larger scale of processors, the probability of faults in the network increases, hence communication must be robust and fault tolerant. The recently introduced family of folded Petersen networks, constructed by iteratively applying the cartesian product operation on the well-known Petersen graph, provides a regular, node– and edge-symmetric architecture with optimal connectivity (hence maximal fault-tolerance), and logarithmic diameter. Compared to the closest sized hypercube, the folded petersen network has a smaller diameter, lower node degree and higher packing density. In this paper, we study fundamental communication primitives like single routing, permutation routing, one-to-all broadcasting, multinode-broadcasting (gossiping), personalized communications like scattering, and total exchange on the folded Petersen networks, considering two communication models, namely single link availability (SLA) and multiple link availability (MLA). We derive lower bounds for these problems and design optimal algorithms in terms of both time and the number of message transmissions. The results are based on the construction of minimal height spanning trees in the fault-free folded Petersen network. We further analyze these communication primitives in faulty networks, where processing nodes and transmission links cease working. This analysis is based on multiple arc-disjoint spanning trees, a construct also useful for analyzing other families of multicomputer networks.