Communication in GLOBE: An Object-Based Worldwide Operating System

Current paradigms for interprocess communication are not sufficient to describe the exchange of information at an adequate level of abstraction. They are either too lowlevel, or their implementations cannot meet performance requirements. As an alternative, we propose distributed shared objects as a unifying concept. These objects offer user-defined operations on shared state, but allow for efficient implementations through replication and distribution of state. In contrast to other object-based models, these implementation aspects are completely hidden from applications. 1 Introduction In the 1960s and 1970s, the computing universe was dominated by mainframes and minicomputers that ran batch and timesharing operating systems. Typical examples of these systems were OS/360 and UNIX. These system were primarily concerned with the efficient and secure sharing of the resources of a single machine among many competing users. In the 1980s, personal computers became popular. These machines h..

A Model for Worldwide Tracking of Distributed Objects

We describe a service for locating distributed objects identified by location-independent object identifiers. An object in our model is physically distributed, with multiple active copies on different machines. Processes must bind to an object in order to invoke its methods. Part of the binding protocol is concerned with contacting the object, which offers one or more contact points. A contact point is associated with an active part of the distributed object, and describes exactly how and where initial communication should take place. An object can change its contact points in the course of time, thus exhibiting migration behavior. Finding an object's contact points is the essence of our location service. Our model is based on a worldwide distributed search tree, capable of handling trillions of distributed objects. The tree adapts dynamically to individual migration patterns. By exploiting an object 's relative stability with respect to a region, combined with the use of pointer caches, an object can be contacted through a search path of only length two. We present the architecture of our location service, including its update and lookup mechanism, and discuss its scalability.

The Architectural Design of Globe: A Wide-Area Distributed System

. Developing large-scale wide-area applications requires an infrastructure that is presently lacking entirely. Currently, applications have to be built on top of raw communication services, such as TCP connections. All additional services, including those for naming, replication, migration, persistence, fault tolerance, and security, have to be implemented for each application anew. Not only is this a waste of effort, it also makes interoperability between different applications difficult or even impossible. We present a novel, object-based framework for developing wide-area distributed applications. The framework is based on the concept of a distributed shared object, which has the characteristic feature that its state can be physically distributed across multiple machines at the same time. All implementation aspects, including communication protocols, replication strategies, and distribution and migration of state, are part of an object and are hidden behind its interface. The curren..

A law-abiding peer-to-peer network for free-software distribution

... for worldwide distribution of freely redistributable software packages. The GDN takes a novel, optimistic approach to stop the illegal distribution of copyrighted and illicit material via the network. Instead of having moderators check the software archives at upload time, illegal content is removed and its uploader's access to the network permanently revoked only when the content is discovered. An important feature of the GDN is that the objects containing the software can run on untrustworthy servers. A first version of the GDN has been implemented and has been running since October 2000 across four European sites

A security architecture for object-based distributed systems

Large-scale distributed systems present numerous security problems not present in local systems. In this paper we present a general security architecture of a large-scale object-based distributed system. Its main features include ways for servers to authenticate clients, clients to authenticate servers, new secure servers to be instantiated without manual intervention, and ways to restrict which client can perform which operation on which object. All of these features are done in a platform- and application-independent way, so the results are quite general. The basic idea behind the scheme is to have each object owner issue cryptographically sealed certificates to users to prove which operations they may request and to servers to prove which operations they are authorized to execute. These certificates are used to ensure secure binding and secure method invocation. The paper discusses the required certificates and security protocols for using them

An Architecture for a Wide Area Distributed System

this paper is part of the Globe Project (Globe stands for GLobal Object Based Environment) . The goal of this project is the design and implementation of a wide area distributed system that provides a convenient programming abstraction and full transparency. The main contribution of this paper is the description of a new system for distributed shared objects. In contrast to other systems, the implementation of distribution, consistency, and replication of state is completely encapsulated in a distributed shared object. This allows for object-specific solutions, and provides the right mechanism for building efficient and truly scalable systems. 2 Problems to be Solve

A Location Service for Worldwide Distributed Objects

This position paper introduces the Globe object model for wide-area distributed systems and its location service. The location service provides transparency of location, migration, distribution, and replication of distributed objects. We present the architecture of the service and briefly discuss scalability.