This overview of C++ presents the key design, programming, and language-technical concepts using examples to give the reader a feel for the language. C++ is a general-purpose programming language with a bias towards systems programming that supports efficient low-level computation, data abstraction, object-oriented programming, and generic programming. 1

One of most serious problems plaguing the World Wide Web today is that of broken hypertext links, which are a major annoyance to browsing users and also a cause of tarnished reputation and possible loss of opportunity for information providers. The root of the problem lies in the current Web architecture's lack of support for referential integrity. This paper presents a model for the provision of referential integrity for Web resources which supports resource migration and tolerates site and communication failures. The approach is object-oriented, highly flexible, completely distributed, and does not require any global administration. An attractive feature of our design is the provision of a lightweight mechanism which provides referential integrity, and which may be customised on a per resource basis to provide increased fault-tolerance and performance. Our system follows an evolutionary approach, supporting parallel operation with the existing Web, allowing users to gain the addition...

The majority of today’s millions of Web sites offer read-only access to relatively small amounts of infrequently changing information. The load on these sites is usually small, and services can often be hosted as background tasks on general-purpose workstations. Concern for the quality of service (QoS) presented to users at these sites is generally not primary. Conversely, a much smaller number of sites are very popular; they support heavy loads and must meet user expectations regarding QoS to maintain their popularity. As perceived by Web service users, QoS depends on several factors. Perhaps the most important of these is availability. Users expect services that are continuously available; a service that is frequently unavailable can tarnish the provider’s reputation. Furthermore, from the user’s perspective, a service that exhibits poor responsiveness is virtually equivalent to one that is unavailable. QoS also encompasses the quality of the information provided, a specific instance being the integrity of hypertext linking between resources. Sites

The Web frequently suffers from failures which affect the performance and consistency of applications run over it. An important fault-tolerance technique is the use of atomic transactions for controlling operations on services. While it has been possible to make server-side Web applications transactional, browsers typically did not possess such facilities. However, with the advent of Java it is now possible to consider empowering browsers so that they can fully participate within transactional applications. In this paper we present the design and implementation of a standards compliant transactional toolkit for the Web. The toolkit allows transactional applications to span Web browsers and servers and supports application specific customisation, so that an application can be made transactional without compromising the security policies operational at browsers and servers.

From a commercial perspective, the Web has promised much more than it has delivered and the dream of worldwide Internet business enterprises has yet to become a reality. Electronic commerce currently resembles a vast, sprawling bazaar in which visitors must wander through countless market stalls. For most potential customers, this is frustrating and time-consuming. In traditional commerce, middlemen, or brokers, make it easier for customers to find, compare and buy because they aggregate goods and services from a variety of sources and display them in a way which is helpful to customers. In the electronic marketplace of the near future, there are likely to be large numbers and varieties of brokers. We believe that the widespread and rapid deployment of brokering services depends upon the availability of building blocks which are sufficiently generic that they can be tailored to produce a wide range of specific brokers. We call this collection of building blocks a generic broker. If such a generic broker framework is not available then specialised brokers will be implemented in an ad-hoc manner with a consequent wastage of effort, while their construction will be beyond the resources and skills of many companies who would otherwise benefit from them. In this paper we present the design of the Metabroker system, a generic framework for the construction of specialist electronic brokers. Our design is based upon the integration of distributed object, metadata and object database technologies.

Prior to 1994, student registration at Newcastle University involved students being registered in a single place, where they would present a form which had previously been filled in by the student and their department. After registration this information was then transferred to a computerised format. The University decided that the entire registration process was to be computerised for the Autumn of 1994, with the admission and registration being carried out at the departments of the students. Such a system has a very high availability requirement: admissions tutors and secretaries must be able to access and create student records (particularly at the start of a new academic year when new students arrive). The Arjuna distributed system has been under development in the Department of Computing Science for many years. Arjuna's design aims are to provide tools to assist in the construction of fault-tolerant, highly available distributed applications using atomic actions (atomic ...

In distributed systems, object replication is used to improve the availability and performance of applications in the presence of failures. When determining the configuration of a replicated object (i.e., number and location of replicas), a number of often conflicting factors need to be considered, e.g., the availability and performance requirements of the object. However, application specific knowledge about the objects, such as any inter-dependencies, is typically not accounted for. In many applications this information can affect an object's availability. Distributed systems which support replication typically give users only basic control over the configuration of a replicated object, such as the number or location of individual replicas. Expressing application specific knowledge is not possible. We have designed and implemented a replication sub-system allowing applications to control these aspects of replication. This system allows the efficient replication of an arbitrary number of objects with arbitrary inter-dependencies.

This overview of C++ presents the key design, programming, and language-technical concepts using examples to give the reader a feel for the language. C++ is a general-purpose programming language with a bias towards systems programming that supports efficient low-level computation, data abstraction, object-oriented programming, and generic programming.

This paper attempts to address the question: Is Java a language that can be used to implement an efficient, and performant transaction system? Having implemented transaction systems in both C++ and Java [GDP95][MCL97b], we believe the experience we have gained can help to answer this question

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