The Distributed ASCI Supercomputer (DAS) is a homogeneous wide-area distributed system consisting of four cluster computers at different locations. DAS has been used for research on communication software, parallel languages and programming systems, schedulers, parallel applications, and distributed applications. The paper gives a preview of the most interesting research results obtained so far in the DAS project.

Product software is constantly evolving through extensions, maintenance, changing requirements, changes in configuration settings, and changing licensing information. Managing evolution of released and deployed product software is a complex and often underestimated problem that has been the cause of many difficulties for both software vendors and customers. This paper presents a process model and typology to characterize techniques that support product software update methods. Also, this paper assesses and surveys a variety of existing techniques against the characterisation framework and lists unsolved problems related to software product updaters.

We describe the algorithmic design of a worldwide location service for distributed objects. A distributed object can reside at multiple locations at the same time, and o ers a set of addresses to allow client processes to contact it. Objects may be highly mobile like, for example, software agents or Web applets. The proposed location service supports regular updates of an object's set of contact addresses, as well as e cient look-up operations. Our design is based on a worldwide distributed search tree in which addresses are stored at di erent levels, depending on the migration pattern of the object. By exploiting an object's relative stability with respect to a region, combined with the use of pointer caches, look-up operations can be made highly e cient.

Keywords: product software, software configuration management, product data management, customer relationship management, software delivery, deployment Integrated Development and MaintenanceThe maintenance, release, and deployment of enterprise application software is a complex task for a software vendor. This complexity is caused by the enormous scale of the undertaking. There are many customers for the vendor to serve, which all might require their own version or variant of the application. Furthermore, the application itself will consist of many (software) components that depend on each other to function correctly. On top of that, these components will evolve over time to answer the changing needs of the customers. As a consequence, the release and deployment of these applications take a significant amount of effort and is a time consuming and error-prone process.To alleviate this problem we envision an intelligent software knowledge base (ISKB) that contains all facts about all artefacts together with their relevant attributes, relations and constraints. In this way, high-quality software configurations can be calculated automatically from a small set of key parameters. It also becomes possible to pose whatif questions about necessary or future upgrades of a customer's configuration. The ISKB can improve the software maintenance processes at both the customer and the software vendor sites.Exact Software (ES), a software manufacturer in the Netherlands serving 160,000 customers worldwide, has implemented an ISKB to manage and improve its software maintenance, release, and deployment processes. The ISKB implemented by ES has been implemented in its own product e-Synergy. In this paper we show that ES successfully supports its large customer base with an integrated product data management (PDM), software configuration management (SCM), and customer relationship management (CRM) system, thereby alleviating the process of software product maintenance. The paper describes how the processes of development, release, and deployment have been improved by integrating processes that were previously managed by utilizing different isolated systems. The paper also demonstrates how a central software knowledge base, containing all the relevant knowledge about software products, is implemented and used to support the processes of software maintenance. Finally, the paper describes four principles employed by ES to deal with general complexities in the software engineering discipline with respect to software maintenance.

In the current Web, Uniform Resource Locators (URLs) are used to name and access resources. However, URLs pose a significant scalability problem in the Web since they cannot be used to refer to replicated Web pages. We propose a new URI scheme called Human-Friendly Names (HFNs) to solve this scalability problem. HFNs are high-level names that are easy-to-use by humans and name Web resources in a location-independent way. We describe the design of a scalable HFN-to-URL resolution mechanism that is based on URNs and makes use of the Domain Name System (DNS) and the Globe Location Service.