The explosion of data volumes in enterprise environments and limited budgets have triggered the need for multi-tiered storage systems. With the bulk of the data being extremely infrequently accessed, tape is a natural fit for storing such data. In this paper we present our approach to a file storage system that seamlessly integrates disk and tape, enabling a bottomless and cost-effective storage architecture that can scale to accommodate Big Data requirements. The proposed system offers access to data through a POSIX filesystem interface under a single global namespace, optimizing the placement of data across disk and tape tiers. Using a self-contained, standardized and open filesystem format on the removable tape media, the proposed system avoids dependence on proprietary software and external metadata servers to access the data stored on tape. By internally managing the tape tier resources, such as tape drives and cartridges, the system relieves the user from the burden of dealing with the complexities of tape storage. Our implementation, which is based on the GPFS and LTFS filesystems, demonstrates the applicability of the proposed architecture in real-world environments. Our experimental evaluation has shown that this is a very promising approach in terms scalability, performance and manageability. The proposed system has been productized by IBM as LTFS Enterprise Edition.

This paper introduces a flexible persistence model for state machine workflows. In contrast to the persistence support in contemporary process definition languages and corresponding workflow engines we propose a model where, firstly, an arbitrary number of persistence providers can be attached to the process engine and, secondly, the workflows can dynamically decide when they should be stored persistently and by which persistence provider. Furthermore, we exemplify the implementation of this model within ePVM, an embeddable process virtual machine based on the theoretical foundation of communicating extended finite state machines. Finally, we present results gained from an initial experiment demonstrating that the model can help increasing software efficiency.

Component-oriented software development has been attracting increasing attention for building complex distributed applications. A new infrastructure supporting this advanced concept is our prototype component framework based on the Grid component model. This paper provides an overview of the component framework and presents a case study where we utilise the component-oriented approach to develop a business process application for a biometric identification system. We then introduce the tools being developed as part of an integrated development environment to enable graphical component-based development of Grid applications. Finally, we report our initial findings and experiences of efficiently using the component framework and set of software tools.

At the heart of every business process management system resides a workflow engine, here termed process execution engine. Yet despite playing such a central role, contemporary business process engines generally still leave much to be desired in terms of interoperability, versatility, and programmability. Therefore, this paper introduces ePVM, an embeddable process execution engine aimed at solving these issues. Basically, ePVM is built upon two core concepts. Firstly, an execution model which is deeply rooted in the theoretical framework of communicating state machines. Secondly, whereas many efforts have been made to create the ultimate process language, ePVM provides in contrast a low-level run-time environment based on a JavaScript interpreter where higher-level domain specific process definition languages can be mapped to. Our work explores both concepts in more detail and also positions ePVM in the current business process and workflow domain.