Salter, R. (September 1999)
History-keeping has surfaced as a potentially valuable asset to educational and other software. Current research in learning histories considers the hypothesis that providing learners with a readable record of their actions may help them monitor their behavior and reflect on their progress. However, the scope of learning histories goes far beyond the means provided by an undo/redo or document-recall history system. In this paper we describe Trails, a component-based framework for constructing rich learning history modules based on the client/server model. Trails historians are loosely-coupled to their client applications and interact with them through a set of well-defined interfaces. Trail historians also provide ample means for history visualization and direct manipulation. The client-server architecture facilitates history extensions to existing applications, while the modular design promotes experimentation with different visualization metaphors.