Versioning in Interactive Systems

Dealing with past states of an interactive system is often difficult, and users often resort to unwieldy methods such as saving and naming multiple copies. Versioning tools can help users save and manipulate different versions of a document, but traditional tools designed for coding are often unsuitable for interactive systems. Supporting versioning in interactive systems requires investigation of how users think about versions and how they want to access and manipulate past states. We first surveyed users to understand what a ‘version’ means to them in the context of digital interactive work, and the circumstances under which they create new versions or go back to previous ones. We then built a versioning tool that can store versions using a variety of explicit and implicit mechanisms and shows a graphical representation of the version tree to allow easy inspection and manipulation. To observe how users used versions in different work contexts, we tested our versioning tool in two interactive systems – a game level editor and a web analysis tool. We report several new findings about how users of interactive systems create versions and use them as undo alternatives, exploring options, and planning future work. Our results show that versioning can be a valuable component that improves the power and usability of interactive systems. The new understanding that we gained about versioning in interactive environments by developing and evaluating our custom version tool can help us design more effective versioning tools for interactive systems

Management of Undo/Redo Operations in Complex Environments

During past thirty years, several models for non-linear undo models have been presented, but almost none solves undoing and redoing actions in environments, where multiple history buffers are involved and when there are causal dependencies among separate actions. This thesis focuses on developing a new model, which allows a user to select any action from any history buffer. The key part of the model is a smart command design and undo manager, which searches for dependencies and offers possible solutions to the user. The results are presented in the context of the DaemonX framework