Rethinking Consistency Management in Real-time Collaborative Editing Systems

Networked computer systems offer much to support collaborative editing of shared documents among users. Increasing concurrent access to shared documents by allowing multiple users to contribute to and/or track changes to these shared documents is the goal of real-time collaborative editing systems (RTCES); yet concurrent access is either limited in existing systems that employ exclusive locking or concurrency control algorithms such as operational transformation (OT) may be employed to enable concurrent access. Unfortunately, such OT based schemes are costly with respect to communication and computation. Further, existing systems are often specialized in their functionality and require users to adopt new, unfamiliar software to enable collaboration. This research discusses our work in improving consistency management in RTCES. We have developed a set of deadlock-free multi-granular dynamic locking algorithms and data structures that maximize concurrent access to shared documents while minimizing communication cost. These algorithms provide a high level of service for concurrent access to the shared document and integrate merge-based or OT-based consistency maintenance policies locally among a subset of the users within a subsection of the document – thus reducing the communication costs in maintaining consistency. Additionally, we have developed client-server and P2P implementations of our hierarchical document management algorithms. Simulations results indicate that our approach achieves significant communication and computation cost savings. We have also developed a hierarchical reduction algorithm that can minimize the space required of RTCES, and this algorithm may be pipelined through our document tree. Further, we have developed an architecture that allows for a heterogeneous set of client editing software to connect with a heterogeneous set of server document repositories via Web services. This architecture supports our algorithms and does not require client or server technologies to be modified – thus it is able to accommodate existing, favored editing and repository tools. Finally, we have developed a prototype benchmark system of our architecture that is responsive to users’ actions and minimizes communication costs

TeNDaX, a Collaborative Database-Based Real-Time Editor System

TeNDaX is a collaborative database-based real-time editor system. TeNDaX is a new approach for word-processing in which documents (i.e. content and structure, tables, images etc.) are stored in a database in a semi-structured way. This supports the provision of collaborative editing and layout, undo- and redo operations, business process definition and execution within documents, security, and awareness. During document creation process and use meta data is gathered automatically. This meta data can then be used for the TeNDaX dynamic folders, data lineage, visual- and text mining and search. We present TeNDaX as a word-processing ‘LAN-Party’: collaborative editing and layout; business process definition and execution; local and global undo- and redo operations; all based on the use of multiple editors and different operating systems. In a second step we demonstrate how one can use the data and meta data to create dynamic folders, visualize data provenance, carry out visual- and text mining and support sophisticated search functionality